An excavator was seen over the weekend digging up the backyard of the home of the suspect in several killings on Ov FinanceNew York's Long Island and the heavy equipment was still behind Rex Heuermann's house Monday morning. According to law enforcement sources, investigators are looking into whether any victims may have been killed at the house, CBS News senior investigative producer Pat Milton reported last week.

Heuermann has been charged with killing three women and is the prime suspect in a fourth in the yearslong investigation into the Gilgo Beach killings. Heuermann pleaded not guilty to murder charges after he was arrested in New York City earlier this month.

Suffolk County Police Commissioner Rodney Harrison told reporters Monday that investigators are using ground-penetrating sonar at the house as well as cadaver dogs, CBS New York's Carolyn Gusoff reported. Harrison said numerous items have been taken from the house and the search of the property should be over in the next day or two.

Investigators have shovels and are digging around the house's foundation, Gusoff reported.  

A wooden deck at the Massapequa Park house Heuermann shared with his wife Asa Ellerup and two adult children has been dismantled and police have put up a tent where the front porch was, Gusoff reported.

According to law enforcement sources, Ellerup and the children were away from the house at the time of the killings, Milton reported. Ellerup filed for divorce last week.

"There's absolutely no evidence that anyone acted with the defendant, much less his family," Suffolk County District Attorney Raymond Tierney told CBS News in an interview.

In:
• Rex Heuermann
• Gilgo Beach
• Long Island

Alex Sundby

Alex Sundby is a senior editor for CBSNews.com

Twitter