HHG-011

Cardholder disputes the charge: Customer C11923 message: 'I never made this $131.30 purchase. Please check my card.' Refers to 3583368.

34 online transaction(s) on card C11923-K2 -- T3576228 ($11.22), T3576269 ($21.98), T3576340 ($33.86), T3576468 ($22.30), T3576872 ($22.21), T3577245 ($33.79), T3577287 ($20.51), T3577440 ($31.30), T3577647 ($35.74), T3578347 ($40.13), T3578817 ($25.73), T3579597 ($26.19), T3580380 ($25.67), T3580403 ($25.76), T3580417 ($25.68), T3580478 ($23.52), T3580544 ($22.07), T3580712 ($44.08), T3580765 ($40.12), T3580776 ($25.08), T3580815 ($15.21), T3580907 ($16.17), T3581048 ($37.08), T3582338 ($36.67), T3582375 ($32.65), T3582413 ($16.63), T3582738 ($56.59), T3582868 ($57.27), T3583101 ($40.56), T3583229 ($16.78), T3583368 ($131.30), T3583406 ($19.55), T3583411 ($6.33), T3583435 ($22.93) -- came from a device first marked 'New' for this account (id_15=New)

Structural match (shared device/region/card) with confirmed-fraud closed case CC-3905 (pattern: card_not_present_new_device)

Precedent (confirming): CC-3905 (confirmed fraud, $1,397.53 exposure): shares 2 entities (card/device/region) with this alert

Precedent (confirming): CC-0583 (confirmed fraud, $31.26 exposure): semantically similar analyst notes (cosine distance 0.29), no direct structural overlap

Precedent (confirming): CC-0533 (confirmed fraud, $79.58 exposure): semantically similar analyst notes (cosine distance 0.30), no direct structural overlap

Precedent (disconfirming): CC-0696 (cleared as legitimate): semantically similar analyst notes (cosine distance 0.32), no direct structural overlap

Precedent (disconfirming): CC-4743 (cleared as legitimate): shares 1 entity (card/device/region) with this alert

Flagged charge matches this customer's own recurring merchant/amount pattern (monthly)

Fraud Policy R7: Forbids immediate card block when disputed charge matches customer's established recurring subscription.

Agent elected to expand the investigation to the shared-device neighbourhood. Reasoning: YES The presence of a new device marker and a closed case match suggests the device may be linked to other compromised accounts, warranting a check for connected cards.

Agent proposed device_neighbors(device_id=device_id_15), refused: that looks like a raw dataset column name, not a real entity id -- running it would waste a query rather than gather evidence. Full params: {'device_id': 'device_id_15', 'anchor': '2016-12-29 06:27:44', 'hours': 72}

card_window returned 107 connected entities at depth 2. Reasoning: The goal is to identify the specific device ID associated with the 'New' marker for card C11923-K2. The identifier 'device_id_15' is not in the known list of real identifiers, so I cannot use it directly in a device_neighbors query. The card_window query will retrieve recent transactions for the card, which should reveal the device IDs used, allowing me to identify the specific device associated with the 'New' marker before proceeding to check for shared usage.

Confidence check on gathered evidence: high -- The evidence presents a clear conflict between the customer's denial and the transaction's alignment with their established baseline. The disputed charge matches the customer's recurring merchant/amount pattern, which is a strong indicator of legitimacy. Furthermore, Policy R7 explicitly forbids immediate card blocking in such scenarios. While there are structural matches to prior fraud cases and a 'New' device marker, the specific nature of the charge as a known recurring subscription outweighs these generic risk signals for the purpose of the policy engine's decision. The investigation has reached its depth limit, and the available signals are sufficient for the policy engine to apply R7 and determine the appropriate action.