An investigation into the background of a Minnetrista man will occur before possible plea negotiations in the drowning of his infant daughter in a vehicle that sank into the icy waters of Lake Minnetonka, according to a Hennepin County District Court action Monday.

A blood test indicated that Jonathan Markle, 42, was legally drunk at the time of the January accident for which he was charged with criminal vehicular homicide. His lawyers lost their attempt exclude a blood sample from Markle showing a .13 percent alcohol content. The blood is a major piece of evidence against him.

Markle’s lawyers, Joe Friedberg and Paul Engh, met for about 30 minutes behind closed doors Monday with a prosecutor and Judge Jay Quam. The judge did not take the bench, but Friedberg spoke to reporters afterward.

The agreed-upon action allows the county’s Probation Department to conduct a pre-plea investigation which involves interviewing a defendant about his mental health, chemical history and background then verifying what he says with other sources.

The final report might be a half-dozen pages and is given to the judge. Usually such reports are prepared in advance of sentencing a convicted defendant. The judge uses the reports to make decisions on sentence lengths.

Friedberg said this report will explore whether Markle “has something in his background we’re unaware of.” The lawyer added, “He doesn’t.”

The report will give the defense and prosecution Markle’s history. “It lets everybody know what they’re dealing with.”

Assenting to an investigation, however, does not mean there will be a plea deal. If the case goes to trial, Friedberg said nothing Markle says to the probation officer can be used against him.

The pre-plea reports, which are not made public, generally take about six weeks to complete. The next court appearance by Markle is scheduled for Oct. 30.

In the meantime, Friedberg said there are no other pending issues in the case.

Markle sat silently by himself in the courtroom Monday as his lawyers met with Quam. After his lawyers emerged, Markle signed the agreement for the investigation, then went to the eighth-floor probation offices. He did not speak to reporters.

His blood alcohol at the time of the Jan. 18 crash was well over the legal limit of .08 percent.

An Orono police officer smelled alcohol on Markle and the test was done within two hours of the family’s sport-utility vehicle crashing through the ice on the channel between Priests and Halstead bays.

Eight-month-old Tabitha was strapped into her car seat. Markle repeatedly dove into the water, trying to save his daughter. She was underwater for more than 15 minutes and died three days later.

Markle’s wife and their 2-year-old daughter were in the vehicle and escaped with hypothermia.