A dispute that started in the layaway department of a Sterling Heights Walmart led to a four-person fight and the pulling of a fire alarm.

According to a video released by police, a young man and his mother were waiting in the crowded layaway room at about 7 p.m. on Monday night.

The man was upset with how his mother was being treated by a female employee behind the counter, said Sterling Heights Lieutenant Mario Bastianelli. The two left the area, but then returned — and encountered the employee's brother, who also works at the store and heard the argument from around the corner.

As customers backed away, the two young men began to exchange blows, at one point moving into the adjacent back room. Then the son left again, only to return a few minutes later with a knife he nabbed from a shopping cart nearby, Bastianelli said.

The video shows him running into the employees-only section, looking for the brother-sister duo. From inside the room, the sister throws several chairs at him.

Another employee tries to calm him down, without realizing he has a knife.

The incident ended when someone pulled the fire alarm and everyone ran out, Bastianelli said.

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The 52-year-old mom was initially questioned by police but was then released.

A warrant has been issued for the son, and police hope to get him in custody today. He is not a Sterling Heights resident.

"This time of year brings these types of incidents out," Bastianelli said. "People tend to be a little more impatient, they're in a rush. It's the holiday season where everyone's trying to get their stuff."

But it's not as common to pull a knife, he added.

The Walmart is located at 14 Mile Road and Van Dyke.