A weekend tip led police to a city man accused of having a bag full of marijuana.

The tipster, police said, was the suspect’s mother.

Police on Saturday arrested William G. Blust III, 21, of Butler on felony and misdemeanor drug charges.

Blust’s 56-year-old mother notified authorities Friday night that she found a “large bag of marijuana” in her son’s room at their home on Maharg Street, according to court documents. The bag was in the clothing drawer in his room.

She also admitted that she knew her son sells the drug, police said.

Police went to the house and took the plastic bag, which contained 231.9 grams — or about one-half pound — of suspect marijuana.

Officers also seized $1,160 in currency that belonged to Blust.

The defendant was not there but his mother again notified police after he returned home. Officers showed up again, this time arresting him.

Blust was arraigned Saturday on charges of possession with intent to deliver a controlled substance and possession of a controlled substance. He was released Sunday after posting $3,000 bail.

Deputy Chief David Adam said that although unusual, other parents have previously turned in their children to city police for using or having drugs.

“It’s somewhat of a surprise but this case wasn’t the first time,” he said. “It’s still a nice surprise to get the drugs off the street.”