Using Power Automate to Route Incoming Evidence Files for Review

Legal teams handle a constant stream of evidence files—emails, photos, videos, PDFs, and forensic exports—all of which must be routed quickly to the right reviewers while preserving chain of custody and compliance. Automation with Microsoft 365 and Power Automate eliminates manual handling, reduces risk, and speeds matters forward. This week’s guide shows how to design and implement a robust, compliant evidence-routing workflow built on Microsoft Teams, SharePoint, and Power Automate.

Table of Contents

• Why Routing Incoming Evidence Files Matters
• Solution Architecture with Microsoft 365 & Power Automate
• Step-by-Step Walkthrough: Build an Evidence Routing Flow
• Compliance & Risk Controls Built-In
• Integrating AI into the Review Pipeline
• ROI & Business Case for Legal Automation
• Operating Model: Roles, Notifications, and SLAs
• Future Trends & Next Steps
• Conclusion

Why Routing Incoming Evidence Files Matters

Manual evidence intake is slow, error-prone, and risky. Files arrive through multiple channels—email, client portals, opposing counsel, and forensic providers—and must be classified, stored, labeled, and assigned for review. Without automation, firms face version sprawl, missed deadlines, and compliance gaps around confidentiality and retention.

Power Automate allows you to capture files from Outlook, Teams, and SharePoint, apply metadata and retention labels, notify the right reviewers in Teams, create Planner tasks, and log chain-of-custody events—all in a single, auditable flow. The result: faster review cycles, lower costs, and stronger defensibility.

[Source Channels]  ->  [Intake Library] -> [Classification] -> [Assignment] -> [Review & Hold]
 Email/Inbox            SharePoint            AI/Rules            Teams/Planner     Purview/eDiscovery
 Teams Channel          OneDrive Drop         Sensitivity         Approvals          Retention Label
 Secure Upload          Client Portal         Retention            Notifications      Audit Log
  

Solution Architecture with Microsoft 365 & Power Automate

Below is a simple, scalable reference architecture for routing evidence using Microsoft 365 services you likely already own.

• Intake Channels:
  • Shared mailbox (e.g., evidence@yourfirm.com) via Outlook
  • Teams channel (secure, private channel per matter)
  • SharePoint “Evidence Intake” library (drag-and-drop or secure external sharing)
• Repository of Record: SharePoint Site per Matter with dedicated Evidence libraries, locked down by Microsoft 365 Groups and sensitivity labels.
• Workflow Orchestration: Power Automate cloud flows for capture, classification, deduplication, metadata enrichment, approvals, and notifications.
• Tasking & Collaboration: Planner buckets for review queues; Teams messages and adaptive cards to alert assigned reviewers.
• Compliance & Security: Microsoft Purview for retention labels, DLP, and audit; Defender for Office/SharePoint for malware scanning.
• Reporting: Power BI dashboards over SharePoint/Dataverse logs for cycle times, volumes, and SLA metrics.

Step-by-Step Walkthrough: Build an Evidence Routing Flow

This walkthrough builds a core flow that captures incoming evidence from a shared mailbox and a SharePoint intake library, classifies it, applies retention, assigns reviewers, and logs the event to Dataverse or a SharePoint list.

1. Prepare Microsoft 365 resources:
   • Create a SharePoint Site per matter (or per client) with an “Evidence Intake” library and an “Evidence Repository” library.
   • Establish a shared mailbox (e.g., evidence@yourfirm.com) reviewed only by the automation and authorized staff.
   • Configure a private Teams channel for the matter. Add a Planner plan with buckets (e.g., Triage, First Pass Review, QC).
   • Create a SharePoint list or Dataverse table named “EvidenceLog” with fields: MatterID, FileName, Source, Uploader, ReceivedTimestamp, Classification, Reviewer, RetentionLabel, Status.
   • Work with compliance to define a Purview retention label (e.g., “Evidence – Litigation Hold”) and any matter-specific sensitivity labels.
2. Build the flow triggers:
   • Trigger A (Email): Use “When a new email arrives in a shared mailbox (V3)” on evidence@yourfirm.com. Filter by Has Attachments = Yes.
   • Trigger B (SharePoint): Use “When a file is created (properties only)” for the Evidence Intake library.
   • Optional: Separate flows per channel for easier maintenance, feeding a common child flow for classification and assignment.
3. Normalize filenames and collect metadata:
   • Parse the subject line or file-drop folder path to extract MatterID and any known tags (e.g., “MTR-2025-0142, Deposition – 2025-03-07”).
   • Construct a standardized filename: MatterID_Date_Source_OriginalName.ext.
   • Store preliminary metadata on the SharePoint item: MatterID, SourceChannel (Email/Teams/Intake), Uploader (From/Created By).
4. Move files to the Repository of Record:
   • Copy or move the file from intake into the matter’s “Evidence Repository” library using “Copy file” then “Delete file” (if policy allows), or “Move file.”
   • Update the item properties to include a unique EvidenceID (GUID) for chain-of-custody references.
5. Classify the file:
   • Branch by file type (pdf, msg, eml, jpg, mp4, zip, pst, etc.).
   • Use basic rules: if from opposing counsel, tag SourceParty = Opposing; if zip archive, set RequiresExtraction = Yes.
   • Optional AI Builder Document Processing to extract key fields (e.g., date/time, participant name) from standardized forms.
6. Apply retention and sensitivity:
   • Use “Send an HTTP request to SharePoint” to apply a retention label to the list item (e.g., “Evidence – Litigation Hold”) via the SetComplianceTag method.
   • If your tenant supports it, apply a sensitivity label or ensure the library enforces a default sensitivity label for all evidence content.
7. Create assignment and notify reviewers:
   • Use “Create a task” in Planner, set bucket to “Triage,” and assign to the matter’s reviewer group or designated attorney.
   • Use “Post adaptive card and wait for a response” (Teams) in the matter’s private channel. Include file link, metadata, and buttons: “Accept Review,” “Escalate,” “Reject.”
   • When accepted, move the task to “First Pass Review” and set Reviewer = Responder.
8. Log chain-of-custody:
   • Write a row to the EvidenceLog with timestamps and the current file URL.
   • Optional: Call an Azure Function via the “HTTP” action to compute a SHA-256 hash of the file content and store it in EvidenceLog.
   • Capture the Teams card response (user and timestamp) for a clear audit trail of acceptance.
9. Handle exceptions and escalations:
   • If attachments fail malware checks (Defender), mark Status = Quarantined and alert the matter security contact.
   • If no reviewer accepts within SLA (e.g., 4 business hours), reassign to a fallback group and @mention the supervising attorney in Teams.
   • Automatically notify eDiscovery managers to consider placing a hold if the matter reaches litigation stage.
10. Reporting:
    • Expose the EvidenceLog in Power BI to track intake volumes, time-to-assignment, first-pass review time, and exceptions by matter.
    • Set alerts for spikes in intake or overdue reviews.

Best practice: Build once, use many times. Maintain a single “Evidence Routing” template flow that dynamically targets the correct matter site, Teams channel, and Planner plan based on the MatterID—so you can onboard new matters in minutes without rewriting automation.

Compliance & Risk Controls Built-In

Legal evidence workflows must protect confidentiality, privilege, and custody integrity. The following controls can be integrated without adding friction to reviewers:

• Security and Access:
  • Use private Teams channels mapped to matter-specific SharePoint sites. Limit membership to need-to-know.
  • Leverage sensitivity labels to restrict external sharing and enforce encryption where appropriate.
• Retention, Hold, and Disposition:
  • Apply Purview retention labels on arrival; automate event-based retention when a matter closes.
  • Keep evidence in a single repository of record. Avoid duplicate storage in personal OneDrive or email.
• Data Loss Prevention (DLP):
  • Enable Purview DLP policies for sensitive info (PII, PHI, financial data). Allow the flow to continue while capturing audit signals; block exfiltration attempts.
• Audit & Chain-of-Custody:
  • Log every state change in EvidenceLog with timestamps and user IDs.
  • Use file hashes (optional add-on) and immutable audit fields to increase defensibility.
• Malware Defense:
  • Rely on Defender for Office 365/SharePoint for safe attachments and scanning. Quarantine flagged items and alert the matter DPO/IT.

Integrating AI into the Review Pipeline

AI can augment classification and triage while preserving confidentiality controls. Consider the following measured integrations:

• AI Builder for forms and receipts:
  • Use AI Builder to extract dates, names, and case references from standardized PDFs, adding structured metadata for search and filtering.
• Content classification and routing:
  • Use keyword rules and heuristics (e.g., “deposition,” “chain-of-custody,” “exhibit”) to route to specialty reviewers or create sub-tags.
• Summarization for triage accelerators:
  • Generate short summaries of long emails or PDFs for first-pass triage using approved tools within your compliance boundary.
• Ethical and privacy safeguards:
  • Ensure any AI service operates within your tenant’s data boundary and does not train on your data unless explicitly permitted.
  • Mask or minimize personal data before sending content to AI actions when feasible, and document the rationale for any automated decisions.

ROI & Business Case for Legal Automation

Evidence handling occurs in nearly every litigation or investigation, so small efficiency gains multiply across matters. A conservative ROI model for a mid-size firm shows compelling returns:

• Baseline assumptions:
  • 50 matters in active litigation; average of 20 new evidence files per week per matter
  • 10 minutes saved per file through automated intake, classification, and assignment
  • Blended hourly cost of $85 for paralegals and junior staff
• Annualized impact:
  • 50 matters × 20 files × 52 weeks = 52,000 files
  • 52,000 × 10 minutes = 520,000 minutes saved (~8,667 hours)
  • 8,667 × $85 ≈ $736,000 in labor value unlocked

Beyond labor savings, the risk reduction from consistent retention labeling and chain-of-custody logging can prevent costly sanctions or disputes about evidence integrity—value that doesn’t always show in spreadsheets but matters profoundly in court.

Operating Model: Roles, Notifications, and SLAs

Automation succeeds when supported by clear roles and service levels. Establish an operating model that aligns legal, IT, and risk stakeholders:

• Roles:
  • Matter Owner: approves configuration, designates reviewer pool, and sets SLA targets.
  • Legal Operations/Paralegal Lead: maintains routing rules and contact lists; monitors dashboards.
  • IT/Compliance: manages labels, DLP policies, and security groups; reviews exceptions.
  • Reviewers: triage and complete tasks via Teams and Planner.
• Notifications and SLAs:
  • Acceptance SLA: 4 business hours to accept or escalate an item in Teams.
  • First-pass review SLA: 24–48 hours depending on file type and volume.
  • Escalation: automatic @mention to supervising attorney and reassign to escalation bucket.

SLA Checkpoints:
  [Intake Received] --(≤15 min)--> [Assigned] --(≤4 hrs)--> [Accepted]
                                  --(≤48 hrs)--> [First Pass Complete]
                                          Exceptions -> [Escalation Bucket + Alert]
  

Tip: Keep your routing rules transparent. A simple mapping of MatterID → Teams Channel → Planner Plan → Reviewer Group makes flows easy to audit, easy to hand off, and resilient when personnel change.

Future Trends & Next Steps

Legal automation is moving toward deeper integration and explainable AI. Expect increasing use of structured schemas for evidence metadata, richer adaptive card experiences in Teams, and standardized connectors into eDiscovery tools. As Microsoft expands Purview and Teams capabilities, firms will more easily enforce holds, run targeted collections, and document provenance from the moment a file enters the environment. Start small—one matter, one channel—and expand as patterns prove themselves.

Conclusion

Routing incoming evidence with Power Automate transforms a high-risk, manual process into a fast, defensible pipeline. By centralizing intake, standardizing classification, enforcing retention, and creating clear review assignments, firms accelerate timelines while strengthening compliance. The approach scales from boutique litigation teams to enterprise legal departments—and you can start with the tools already in Microsoft 365. The earlier you automate, the sooner you reduce risk and improve client service.

Ready to explore how Microsoft automation can streamline your firm’s legal workflows? Reach out to A.I. Solutions today for expert guidance and tailored strategies.