The National Transportation Safety Board increased the fatality number from a small plane crash in Watsonville from two to four people.
Officials said two adults and two children were on board the plane when it slammed into a office building adjacent to the Watsonville Community Hospital around 7:30 p.m. Thursday.
They did not identify the victims or their relationship to one another. Friends, however, told KSBW that the pilot was David Houghton, of Santa Cruz. They said he was flying his own plane from Watsonville to Pine Mountain Lake in the Sierra Nevada.
Another family friend told NBC Bay Area that the man was taking his wife Dede and their two children, Luke and Ryan, to Yosemite for a camping trip.
"They were an adventurous family full of love for one another and will be greatly missed," Heidi Langenbacher said.
Witnesses report that the plane took a nose dive and crash landed into the parking lot before sliding some 50 feet into the first floor of the medical building. The hospital is just a few blocks from the Watsonville Municipal Airport. They said the plane immediately burst into flames.
Thomas Arnold told the Santa Cruz Sentinel that he was in the parking lot next to the hospital's administration building when he heard the plane overhead. "I saw two faces and two big sets of eyes,'' Arnold told the paper.
Because the crash happened after hours, no one was in the building when the plane hit. The plane reportedly hit the offices of Dr. Cheryl Northey, an obstetrician.
The hospital was not evacuated, according to emergency officials.
Initially it was believed that two people were on the plane, but the coroner found four bodies inside the 1974 single-engine Mooney M20.