Mequon — The man arrested under suspicion of killing a husband and wife in an upscale Mequon neighborhood is the couple's son, police said Wednesday.

The Ozaukee County district attorney expects to bring charges Thursday against Dennis Markov, 20. He was being held Wednesday in the Ozaukee County Jail on two counts of intentional homicide and two counts of hiding a corpse.

Police said they were called to a house in the 3200 block of W. Fleur de Lis Drive at 2:38 p.m. Tuesday for a check on the welfare of Larissa Markov, 39, who had not shown up for work. The couple's son, who lived there, let officers into the house. They found the bodies of Larissa and her husband, Victor Markov, 45, in the garage.

Police immediately arrested the son.

"This appears to be an isolated incident, and there is no additional threat to our residents," Police Chief Steve Graff said in a news release.

After conducting autopsies on the bodies Wednesday, the Milwaukee County medical examiner's office confirmed that the deaths were homicides. Mequon police did not release any information on the manner of death. Mequon police are still investigating the incident along with the state Department of Criminal Investigation and the State Patrol Technical Reconstruction Unit. Police said they would release further information as it becomes available.

Neighbors said the Markovs were Russian immigrants. Records show they had lived in the house since 2008. The property is worth nearly $300,000, according to the assessor's office.

Neighbors, including Maco Balkovec, were surprised that the incident would take place in the quiet Ville du Parc neighborhood.

"It's very quiet in here. There's a lot of older couples still here and some younger families moving in," Balkovec said. "I heard nothing. There were no signs of any issues going on."

Another neighbor, Shari Butler, said she had approached police near the scene, asking if neighbors "needed to be worried about anything." She said police at the scene didn't say anything.

When police brought the son out of the house shortly before 3 p.m. on Tuesday, he wasn't struggling, she said.

Ozaukee County court records show Dennis Markov was ticketed for underage drinking and possession of drug paraphernalia in mid-April 2010. The charges were amended, and he pleaded guilty to disorderly conduct and paid a fine of $263.50.

He also has tickets for speeding and driving without a seat belt, records show.

The last homicide in Mequon occurred less than half a mile away in January 2006. Stephen L. Trattner pleaded guilty to reckless homicide in the strangulation death of his wife, Sin Lam, who had just told him she wanted a divorce.