Orem police Sgt. Craig Martinez said there were no signs of trauma on the bodies. The police department is waiting for the results of autopsies.
"It's still so early on in the investigation, we can't even say what the cause of death is," Martinez said.
Berg was released from the Utah County jail on Thursday.
Martinez said a Berg family member was concerned about him after he couldn't be reached by phone about an appointment, so the family member went to his home, 479 E. 1450 North, and found Berg and the woman dead.
Police on Monday used yellow tape to cordon the cul-de-sac that included Berg's home. Detectives and evidence technicians moved in and out of the house until about 3:30 p.m.
Berg appeared to have successful practice at the Cosmetic Plastic Surgery Institute in Orem. Then on Nov. 6., according to charging documents, Berg attacked Schwartz in his home, grabbing her hair and dragging her to a bedroom closet.
During the altercation, Schwartz managed to dial 911 from a bathroom phone, which she left off the hook, the charges state. In the recording, nothing is said directly into the phone but a woman can be heard pleading for a man to stop.
Berg tied Schwartz's hands and tried to stop her from screaming by covering her mouth, first with his hands and then with a cloth, court documents state.
After 20 minutes of knocking, according to court documents, police forced their way into the home and found Schwartz bound and kneeling in a closet.
In April, Berg pleaded guilty to a reduced count of second-degree felony kidnapping and two third-degree felony counts of possession of a controlled substance and possession of a firearm by a restricted person. He admitted an addiction to pain killers. He was sentenced to 180 days in jail followed by 36 months of probation, including anger management and substance abuse treatment.
Utah County jail records show Berg reported there April 25 and was released Thursday. A jail employee on Monday said Berg was released early for good behavior.
At his sentencing in April, Berg's attorney admitted his client was addicted to pain killers.
Schwartz spoke at the sentencing on Berg's behalf. Schwartz said she and Berg were still together.
"I know in my heart he will be back and regain the success he had before the addiction took hold," she said at the hearing.
In Schwartz's July 17 letter, she asked Judge Samuel McVey to release Berg from jail early to resume a substance abuse and domestic violence class he attended before entering jail.
Berg wrote a letter to McVey on June 26. He asked for an early release to continue counseling and because "my health has significantly deteriorated in Jail." Berg said he was recovering from back surgery that included bone grafting and spinal fusion. He complained of numbness in his lower body and wanted to participate in physical therapy.
"Please do not require me to jeopardize my life long health and my ability to actively play outdoors with my children and grandchildren," Berg wrote.
Berg also wrote that he had to sell his home "prior to foreclosure."
Berg said he and Schwartz wanted to marry this summer after his 8-year-old daughter was baptized into the LDS Church. Berg implied he would perform the baptism.
The Utah Division of Occupational and Professional Licensing (DOPL) suspended Berg's medical licenses on Nov. 30, 2011, after an emergency hearing. The suspension applied to Berg's physician and surgeon license, and his controlled substance prescribing license. In the suspension order, DOPL said Berg's staff had quit en masse the previous summer because of his strange behavior: falling asleep standing up, swallowing handfuls of pills and buying drugs not used in his practice.
Berg could have appealed the suspension, but in early January 2012, he surrendered his license to practice medicine and agreed not to reapply for three years and until he completed treatment and probation.
Aaron Falk contributed to this report.