(AP) Authorities arrested a plumber suspected of slitting a woman's throat outside her secluded Macomb County home and dumping her body in a lake.

Divers were expected to search Cass Lake Monday morning for the body of Marilou Johnson.

Macomb County Sheriff Mark Hackel said divers from his office and the Oakland County sheriff's department were going to search a part of the West Bloomfield Township lake believed to be about 20 feet deep.

"We got some great information that was substantiated by the actual person we have in custody that her body is in this lake," Hackel said. "It depends on where he took her and where he paddled her out to."

David J. Wright was expected to be arraigned Monday in Johnson's death.

Hackel said Wright, 37, of Richmond, was named in a warrant charging him with open murder, kidnapping and larceny in a building.

Asked if investigators had determined a motive, the sheriff said, "It was money."

"We know he knew the family and probably knew about their financial situation and took advantage of them in a desperate time," Hackel told WWJ-AM on Monday. "Marilou is dead as a result of this guy wanting some money."

Johnson, 50, last was seen June 14 at her Washington Township home about 30 miles north of Detroit, where she lived with her boyfriend, Roger Blanchard, and her three sons from a previous relationship. Blanchard reported her missing the following night.

Wright had gone to the home to give an estimate for plumbing work when, Hackel said, he attacked Johnson in the driveway and cut her throat. Wright then loaded her body into his van, went into the house and stole jewelry belonging to the woman, the sheriff said.

Other people inside the house at the time of the attack apparently did not hear anything. There were no other suspects, Hackel said.

Police knew Wright had gone to the house June 14 and placed him under surveillance shortly after Johnson disappeared, Hackel said. They stopped his van Saturday afternoon in Roseville because it had an improper license plate and found on him a pill bottle containing five diamonds that matched those in a photograph of a necklace worn by Johnson, the sheriff said.

Wright was booked for receiving and concealing stolen property. After interviewing him further, Wright "led us to an area where we think we're going to be able to recover a body," Hackel said.

Blanchard, Johnson's sons and Wright's family cooperated with investigators, he said.