A St. Paul man suspected of robbing a Roseville dollar store on Christmas Eve was quickly identified after forgetting to put on his mask.

Quincy G. Petty, 39, strode into the Dollar Tree on Larpenteur Avenue just after 8 a.m. and approached the cashier, saying, “Open your register, I’m robbing you,” according to charges filed last week. A store employee recognized the suspect as a colleague’s boyfriend before he remembered to put on his mask, court records show.

Petty and a male accomplice left the store with about $1,700 in cash, police said.

He was later arrested outside his girlfriend’s home, where authorities found more than $600 in his pocket along with a crumpled-up envelope with the word “robbery” written on it.

Petty faces one count each of aggravated robbery and simple robbery.

According to the charges, a Dollar Tree manager had recently received a report that a fellow employee heard Petty’s girlfriend make comments about robbing the store, saying her boyfriend was in a gang.

On Christmas Eve, Petty and another man walked in demanding cash on his girlfriend’s day off.

Petty then reached under his sweatshirt near his waistband and yelled: “If you put your hands down, ya’ll done,” according to charges. He then made several remarks about the store’s apparent lack of video cameras.

The men left in a red Ford SUV after forcing managers to empty a safe. Employees told police they believed they were going to be shot during the holdup.

Within hours, authorities tracked Petty to his girlfriend’s house nearby, where his SUV was parked out front. The girlfriend claimed Petty had stayed home with her all morning and accused the store of setting him up in retaliation for a complaint she filed.

Petty denied all involvement, challenging officers to find video evidence of the crime.