SOUTH PORTLAND — An investigation of drug trafficking in a hotel near the Maine Mall led to the arrests of a 60-year-old woman from Massachusetts and her son and the seizure of drugs and cash.

Mattie Brown, of Randolph, Mass., was arrested on Sunday and charged with aggravated trafficking in heroin and trafficking in cocaine. Her son, Robert Brown, 39, also from Massachusetts, was arrested and charged with refusal to submit to arrest and detention.

South Portland Police Lt. Todd Bernard said the department conducted a brief investigation after receiving an anonymous tip of possible drug activity. He said the arrests were made during a traffic stop around 12:30 p.m. Sunday on Western Avenue near the Portland line.

Police searched the hotel room where Brown had been staying and seized more than 50 grams of heroin, an ounce of cocaine, several Oxycontin and Oxycodone pills and close to $10,000 in cash.

Mattie Brown is being held at Cumberland County Jail. Her bail is set at $100,000 cash with a condition that she can’t leave the state. Her son posted bail and was released.

Bernard said the department is continuing its investigation and is working with the Maine Drug Enforcement Agency and Boston Police.