LOWELL -- Police were called to the Metro PCS store at 1776 Middlesex St. at about 4 p.m. Saturday for what was reported by the store manager to be an attempted robbery by two male suspects wearing masks and armed with handguns, according to police radio reports.

The manager locked the doors of the store and called police. The suspects fled on foot. Lowell officers at the scene placed a request for the Chelmsford police K-9 unit to assist in the search.

The investigation remained open late Saturday night, police said.

The same store was robbed last Oct. 12 by a male suspect who reportedly showed a black handgun, possibly a BB gun, and fled with a cellphone.

Anyone with information is asked to call Lowell police at 978-937-3200 or Crimestoppers at 978-459-TIPS (8477).

Tipsters can remain anonymous, but can receive up to $1,000 for information leading to an arrest.

-- JOHN COLLINS