MARENGO, Iowa (AP) — Data from an iPhone and Apple Watch helped lead police to suspects after a woman’s body was found in an Iowa lake, authorities said.

Iowa County Sheriff Robert Rotter on Tuesday identified the victim as 20-year-old Melody M. Hoffman of Marion, Iowa. Her body was discovered Sunday at the Amana Lily Lake.

A 23-year-old man who police say was in a relationship with Hoffman, and an 18-year-old man, were charged Wednesday with first-degree murder and kidnapping.

Hoffman’s body had stab and slash wounds, and a state medical examiner determined she had died by strangulation, according to a police complaint.

The complaint said investigators were able to determine the location of the body in part by tracking information from her watch and phone. Police learned that Hoffman was at Morgan Creek Park near Cedar Rapids on Feb. 16. The complaint said information from her watch “recorded her heartbeat intensify before it either stopped or the device deactivated.”

Police found the Apple Watch with blood on it and other evidence in the trunk of the car belonging to the man she was involved with, the complaint said. He told police that he and another person used duct tape to bind Hoffman at the park and placed her in the trunk, then drove her to the pond, the complaint stated.