Napa police are investigating the drowning death of former state Senate President Pro Tem Don Perata's daughter-in-law, who was found in her home's swimming pool Saturday morning.

Family members found Catherine Perata, 38, dead shortly before 9 a.m. Saturday, said Napa police Capt. Jeff Troendly, and an autopsy conducted Monday found she had drowned.

"Now we're waiting for toxicology to come back and see how that played into any part of this," he said, adding those tests might take a few weeks.

"Right now we're still in the process of interviewing some people, getting more information and background on Ms. Perata, everything leading up to that evening and to her demise," Troendly said, noting she was last seen alive Friday night.

Catherine Perata and her husband, Nick, 40, in 2009 founded a wine country tour company, Perata Luxury Tours & Car Services; the couple has two daughters. Nick Perata is the son of Don Perata, 67, of Orinda, who was the California state Senate's president pro tem from 2004 to 2008, and unsuccessfully sought the Oakland mayor's office in 2010. Earlier, Don Perata was a state senator from 1998 to 2004; an assemblyman from 1996 to 1998; a 1994 primary candidate for state controller; and an Alameda County Supervisor from 1986 to 1994.

Don Perata didn't return a phone call seeking comment Monday.

The family endured tough times as the FBI probed the financial and political relationships between Don and Nick Perata and a wide range of associates. The years-long public corruption investigation ended in 2009 with no charges filed against anyone, but not before agents had served search warrants at sites including both Don and Nick Perata's Oakland homes.

Troendly said the Napa County Major Crimes Task Force aided the investigation not because of a suspicion of foul play, but only because Napa police were already stretched thin by the massive BottleRock Napa concert festival that ran through the weekend.

Josh Richman covers politics. Contact him at 510-208-6428. Follow him at Twitter.com/josh_richman. Read the Political Blotter at IBAbuzz.com/politics.