Officers with the St. Mary's County Bureau of Criminal Investigations arrested 22 people during an operation that unfolded over four hours at two residences and a trailer in Mechanicsville that authorities said were known to be a haven for drug activity.

The investigation had been underway for about two months before authorities from several law enforcement agencies went to the property on Kavanaugh Road last Thursday afternoon with three search warrants, said Lt. Daniel Alioto of the of criminal investigations unit. The initial raid resulted in four arrests, the recovery of 113 grams of crack cocaine with a street value of $11,400, five firearms, $15,405 in cash and several items of stolen property, including power tools and an all-terrain vehicle, police said.

Police arrested William C. Toye, 40, of Mechanicsville, Francis V. Chase, 53, of Mechanicsville, Juwaan M. Carroll, 20, of Lexington Park and Travis L. Butler, 24, of Mechanicsville in the initial raid. All four were released on bail.

Toye was taken into custody on previously outstanding warrants. Chase was charged with conspiracy to distribute crack cocaine. Carroll and Butler were charged with possession of marijuana. Alioto said authorities expect to file additional charges against all four before the investigation is completed. The four could not be reached for comment.

He said the operation a week ago involved 25 to 30 officers from agencies that included the sheriff's office, the Maryland State Police, the Calvert County Emergency Services Team and St. Mary's County Animal Control.

"That was unbelievably successful," Alioto said of the raid. "I know everybody wants an instant solution to the drug epidemic, but all we can do is take chunks out of it."

Once they were in control of the premises, the officers posed as dealers selling crack cocaine. The undercover officers received a steady stream of unsuspecting customers over the next few hours, Alioto said, and made 18 more arrests on charges of purchasing a non-controlled substance believed to be crack cocaine.

Police said the people who came to the house during the undercover operation sought to purchase crack in amounts worth between $20 and $100, and the customers ranged in age from 25 to 53 with an average age of 40.

"All walks of life came in there to buy drugs," Alioto said, including mothers with their babies.

Animal Control officers also responded because there were more than a dozen dogs being kept in deplorable conditions, Alioto said. Some of the dogs were dead, and others were emaciated, he said. A pit bull had clear signs of having been used in dog fights, he said.

"We seized all the dogs, and they will not be returned," Alioto said.

St. Mary's County Commissioner Thomas A. Mattingly Sr. (D-Leonardtown) sat in on a briefing about the operation and said "it was very impressive the amount of people they brought together" and "it appeared to be very, very successful."

Alioto said additional arrests and charges will be forthcoming.