A longtime business rival of Donald Trump delivered what appeared to be a withering takedown of the president’s boasts that he’s in the clear now that special counsel Robert Mueller has produced his investigative report.

According to a summary of the report released by Attorney General William Barr, Mueller was unable to “establish” that there was any collusion between the Trump campaign and the Russian government but that the report did not exonerate the president of obstruction of justice. New York real estate developer Douglas Durst tweeted Thursday that obstruction charges can make the world “safer.”

He should know. His brother, Robert Durst, the subject of a chilling 2015 HBO crime documentary series “The Jinx,” has faced accusations in a number of deaths, including of his wife and best friend. He’s currently in prison in Los Angeles on a weapons conviction as he awaits another murder trial after being acquitted in an earlier one.

Douglas Durst credited obstruction charges with getting his brother off the street after the acquittal. It wasn’t immediately clear when such a charge was brought against his brother. Robert Durst faces trial in California later this year for allegedly killing his friend Susan Berman to hide a previous slaying.