(Adds detail from state prosecutor's office)
SAN FRANCISCO, May 4 (Reuters) - SurveyMonkey Chief Executive Dave Goldberg died Friday from a head injury while exercising at a hotel gym in Mexico, the local prosecutor's office said Monday.
Goldberg, the husband of Facebook Inc Chief Operating Officer Sheryl Sandberg, fell off a treadmill at the Four Seasons Resort in Punta Mita and hit his head, the prosecutor's spokesman said.
Goldberg's brother found him on the floor of the gym showing signs of life, the spokesman said. He was taken to the hospital, where he later died.
No criminal investigation is planned as there were no signs of violence, the spokesman said.
The Four Seasons hotel at Punta Mita denied the reports.
The general manager at the Four Seasons said that Goldberg had not been a guest and that the accident had not taken place at the Four Seasons.
Goldberg's brother announced his death on Saturday morning via a Facebook post, and SurveyMonkey also put out a short statement.
One of Silicon Valley's most admired entrepreneurs, Goldberg was known for his low-key demeanor and the grace and good humor with which he handled being married to one of the nation's most recognizable executives.
Under his leadership, privately held poll-taking company SurveyMonkey grew into a $2 billion business.
A memorial service for Goldberg will be held on Tuesday at Stanford University, according to friends of the family.
Reporting by Sarah McBride, Simon Gardner and Michelle Conlin; Editing by Richard Chang, Bernard Orr