Acting on a confidential tip, Maryland State Police officers discovered eight illegal firearms--including a submachine gun--at a St. Mary's County trailer park on Monday evening. Two residents, both of Park Hall, were arrested and two others might be charged, police said.

William Albert Windsor, 50, and Daniel Albert Humpleby, 27, were charged with illegal possession of firearms after police discovered a cache of weapons that included two revolvers, a 9mm German submachine gun, two shotguns, a rifle and two other semiautomatic firearms, according to information from the Maryland State Police in Leonardtown.

Trooper 1st Class Charles Ewing said he received a tip that Windsor owned several guns, which would be a violation of his parole on an earlier felony conviction and of state laws against owning regulated firearms.

Ewing visited Windsor's home in Garrett Trailer Park, but Windsor denied owning any weapons. Ewing said police then observed cars apparently transporting the guns to Humpleby's trailer nearby. Humpleby was arrested, Ewing said.

In statements to police, Ewing said, Windsor acknowledged that the guns were his and that Humpleby was trying to hide the guns in case officers returned with a search warrant. During the investigation, Ewing said, guns were discovered in two other trailers in the park.

None of the guns was registered, and an official trace is pending to determine how and when the weapons ended up in Southern Maryland.

"The machine gun is not an everyday gun you run across," Ewing said. He also said the Bureau of Alcohol, Tobacco and Firearms would be notified of the case.

Jerry Skalby, property manager of the 30-lot trailer park, said Monday's arrests came as a shock to him. Skalby said that he has known Windsor and his wife for two years and that he had no idea the trailer housed a small arsenal. "He never showed [the guns], never brought them out, never bragged about them," Skalby said. "That machine gun was a collector's piece, probably worth about $2,300. Even the state troopers were shocked at that."

Humpleby and Windsor were released on personal recognizance, said a St. Mary's County Detention Center officer.

On Aug. 7, the Southern Maryland Narcotics Task Force raided two trailers at Garrett and found $5,100 worth of crack cocaine and some marijuana, said Sgt. Kenneth Cusic of the vice-narcotics division of the St. Mary's County sheriff's office. Skalby said the owners of the park intend to work with law enforcement officials to cut down on crime on the grounds.