The country is rallying around 9-year-old Arlo Schmidt, who was the only one in his family to survive an attack while camping in Iowa.
Tyler and Sarah Schmidt, both 42, were shot dead alongside their daughter Lula, 6.
The killings took place as the Cedar Hills family camped in the the Maquoketa Caves State Park campground, officials said.
The Iowa Department of Public Safety released information about the attacks.
"At about 6:23 a.m. this morning, the Jackson County Sheriff's Office and DCI were notified of a triple homicide at the Maquoketa Caves State Park campground," Friday's statement from the Iowa Department of Public Safety. "Officers located three deceased bodies."
Police found the killer, Anthony Orlando Sherwin, 23, dead in the west of the park.
"Sherwin appears to have suffered a self-inflicted gunshot wound, and there is no danger to the public," police said in a statement.
Maquoketa Caves State Park has been closed until further notice. This is an ongoing investigation.
The Iowa Office of the State Medical Examiner will conduct autopsies on all three victims and on the suspect and will release the findings once completed. Police have not indicated how they were killed and whether Arlo suffered any injuries.
"Law enforcement would like to thank the public for their assistance with the investigation and their concern for the Schmidt family," police wrote. "Investigators do not believe there is an on-going risk to the public."
Cedar Falls Mayor Rob Green confirmed the deaths in a Facebook post.
"This morning, our neighbor and Cedar Falls Public Library employee Sarah Schmidt, along with her husband Tyler, and daughter Lula lost their lives to a 23-year-old gunman who then took his own life," Green wrote. "Details will be forthcoming about services and other memorials, and I will ensure the community knows about this. Please offer some extra grace to the Schmidts' many friends, neighbors, and coworkers as we try to process this horrible tragedy."
Green released another statement sharing a GoFundMe page in support of Arlo. More than $220,000 has been raised to date.
A relative who created the page in support of Arlo wrote, "Arlo is a strong boy, surrounded by family and friends who are supporting him as best we can."
