Armed thieves force victims to unlock phones before taking them

CHICAGO (WLS) -- Robbery victims were forced to unlock their phones and reset them to factory settings by armed male offenders in Chicago's Loop and South Loop neighborhoods, police said.

The two offenders were carrying a semi-automatic handgun and demanding cellphones, wallets and purses in three incidents from Aug. 29 - Sept. 1.

The thieves also demanded PIN numbers for victim's bank cards, according to a community alert issued by Chicago police on Saturday.

The incidents occurred at the following times and places:

- Aug. 29 at 1 a.m. in the 900-block of South Michigan Avenue

- Aug. 31 at 12:30 a.m. in the 1200-block of South Lake Shore Drive

- Sept. 1 at 1:15 a.m. in the 500-block of South Columbus Drive

One offender was described as between the ages of 15 and 17 and wearing a black hat with yellow writing on it. The other man was between the ages of 17 and 22 and also wearing a black hat with a Batman logo on it. Both were wearing dark or black clothing.