An emergency room doctor at Fairview Southdale Hospital in Edina found it unsettling that Stephanie Castillo asked about receiving insurance benefits 20 minutes after her 2-month-old son died, according to a search warrant affidavit filed this week in Hennepin County.

The doctor said Castillo was unusually upset when told an autopsy would be performed, the document shows. The baby’s July 18 death is under investigation by Eden Prairie police, they confirmed Thursday. Castillo, 42, of Eden Prairie, has not been charged in the boy’s death, and the Hennepin County medical examiner’s office hasn’t released the cause of his death.

Castillo, who couldn’t be reached for comment Thursday, was charged in January with embezzling more than $1.3 million. She was six months pregnant at the time. Authorities say Castillo, who was vice president of a Golden Valley property management company, embezzled money from four companies, starting in 2009, to feed a shopping addiction and to fund her husband’s business in Mexico.

According to the search warrant affidavit filed Monday, she drove her son to the hospital about 8 a.m. on July 18. He was unresponsive when she arrived, and she told doctors she had found him unresponsive in his crib. Her 3-year-old son was lying next to him in the crib, she said.

The boy died about 40 minutes after being brought to the hospital. The doctor said Castillo was “appropriately upset,” but 20 minutes later asked how soon death benefits would be paid, the document said. The doctor consulted with her primary physician and learned that Castillo was the subject of a pending criminal case for embezzlement.

When police interviewed the doctor less than an hour after the baby died, she told a detective that the boy’s initial laboratory results hadn’t been favorable for his recovery. She didn’t speculate on the cause of the baby’s death, the court document said.

Castillo’s trial on the embezzlement charges is expected to start Sept. 16. She was charged with eight counts of felony theft by swindle. She turned herself in to police in January and posted $300,000 bail.

When approached by police last October about the embezzlement allegations, Castillo, who provided property management and leasing services for Balderson Management, confessed to stealing $1.3 million, said County Attorney Mike Freeman.

Freeman said it is the largest embezzlement case prosecuted by his office, and that he was amazed anyone could systematically take that much money over five years. Because of the length of time and dollar amount, his office will ask for a sentence significantly longer than that recommended in state guidelines, which is 49 to 68 months, he said.

Castillo, who had access to clients’ funds, drafted fake invoices for vendor services and applied some of the payments to company records, charges say. The final step was creating hundreds of fraudulent checks and forging her mother’s signature. The fraud began with a theft of about $50,000 every six months, charges say. In the final six-month period, Castillo took nearly $300,000. She wrote more than 400 checks in five years.