Now police have gotten involved in the nasty spat between Drew Peterson’s lawyers.

Former lead attorney Joel Brodsky filed a report with Chicago Police after receiving what he called a threatening email Wednesday from his one-time co-counsel, Steve Greenberg.

According to the police report, Greenberg wrote that if Brodsky didn’t withdraw “false allegations” made earlier in a legal filing, “your failure to retract will have consequences.”

“This is clearly meant to threaten me, so I notified authorities,” Brodsky said Friday, describing Greenberg as “unstable.”

Brodsky, however, hasn’t sought an order of protection against Greenberg.

For his part, Greenberg denied anything in his email was a threat, though he hinted at legal action against Brodsky, who has withdrawn from Peterson’s defense team.

“In the spirit of the holiday, I thought I would charitably ask him to withdraw slanderous allegations against me and others before moving to have him heavily sanctioned,” Greenberg said.

Earlier this week, Brodsky filed a court document claiming Greenberg was “mentally ill” and leaked sealed documents to a newspaper reporter during Peterson’s murder trial.

That legal filing came after Greenberg sought a new trial for the 58-year-old Peterson, arguing Brodsky bungled his defense of the former Bolingbrook cop.

The fighting between the attorneys has helped delay sentencing for Peterson, who was convicted last September of the 2004 murder of his third wife, Kathleen Savio.