DES MOINES, Iowa – An autopsy released Thursday revealed the causes of death for three family members who were killed at an Iowa state park last month, as well as for the man believed to have killed them.

The bodies of the Cedar Falls, Iowa, family were found at the Maquoketa Caves State Park on July 22; their deaths have been ruled homicides, WHO reports. The family had recently moved to Iowa from Lawrence, Kansas.

Tyler Schmidt, 42, was killed by a gunshot wound and “multiple sharp force injuries,” according to an Iowa Department of Public Safety news release. Sarah Schmidt, 42, died of multiple sharp force injuries, and 6-year-old Lula Schmidt died from a gunshot wound and strangulation.

Investigators previously said a fourth family member, 9-year-old Arlo Schmidt, survived the attack without physical injury. As of Thursday, it wasn’t clear whether or not he was in the tent when the deadly attack happened.

Anthony Orlando Sherwin (Iowa Department of Public Safety via AP)

The cause of death for 23-year-old Anthony Sherwin, of LaVista, Nebraska, who the department said killed the Schmidts, was a self-inflicted gunshot wound. Investigators found Sherwin’s body in a wooded area outside of the campground.

Investigators have said they don’t know what caused Sherwin to attack the family.

No other information was released by the DCI.

The DCI is continuing its investigation into the deaths, but said in the release, “However, the known facts and circumstances, and all evidence collected to this point, substantiate Sherwin was the perpetrator of the homicides and acted alone.”

The Associated Press contributed to this report.

📲 Download the FOX4 News app to stay updated on the go.
📧 Sign up for FOX4 email alerts to have breaking news sent to your inbox.
💻 Find today’s top stories on for Kansas City and all of Kansas and Missouri.