A suburban Virginia husband and wife were arrested yesterday in connection with an alleged murder-for-hire plot after an undercover D.C. police detective was given $5,000 intended as the final payment in the scheme, authorities reported.

The arrests culminated an investigation that began Tuesday when the D.C. detective heard that a woman was "inquiring in the District of Columbia for a hit man" to kill a Prince William County resident, according to county police.

The intended victim of the alleged plot, who was unharmed, was identified only as the employer of one of the two suspects.

The two were identified as Arvel Roy McKinney, 37, and his wife, Catherine McKinney, 40, of Manassas. Authorities said he works in construction and she is in the computer field.

According to a statement issued last night by Prince William police, second district D.C. detective Vince Tolson received information Tuesday that a woman was asking about a hit man, and he contacted the woman "to confirm the sincerity of the request."

Tolson, according to the statement, then contacted Prince William police, and he and county police investigator Henry Wood got in touch with the woman again.

On Wednesday night, according to investigators, the intended victim was in protective custody at an undisclosed location, and yesterday, according to the police statement, the woman "was informed that the hit was made."

Police said arrangements were made for a meeting "to complete payment for the job."

The alleged $5,000 payment was made about 11:40 a.m. in the parking lot of the Prince William County hospital, police said. After the money was given to Tolson, Mrs. McKinney was placed under arrest.

Her husband was arrested about 4:15 p.m. as he returned home from work, police said.

Authorities said each was charged with conspiracy to commit murder for hire. They were being held last night under $50,000 bond in the county jail.