BREAKING: Three Tesla Executives Die In Plane Crash in Palo Alto

In what Tesla Chief Executive Officer Elon Musk is calling "the worst day in Tesla history", three Tesla executives were killed today in a small plane crash in Palo Alto, California.

The names of the three victims are unclear, but the San Francisco Chronicle reports that the plane was owned by Doug Bourn, a senior electrical engineer for Tesla Motors. As the names have not been confirmed, it is unclear if he was onboard. They were only identified as high-ranking executives of Tesla Motors, along with two other employees.

UPDATE: Tesla VP of Communications Ricardo Reyes & VP Diarmuid O'Connel were not on board the flight.

The plane is a twin-engined Cessna 110, manufactured in 1976 and registered to Air Unique, Incorporated in Santa Clara, California. The cause of the crash is unclear, but the plane hit into a tower that is reportedly 80 to 100 feet-tall at 7:55 a.m today. The top half of the structure come off upon impact, with debris landing on a home daycare center on 1225 Beech Street, along with other houses and vehicles on the street, which is about 200 feet away from the site of the impact.

Fortunately, no-one on the ground was injured from the reports we've been hearing.

The crash destroyed electrical-transmission lines running to Palo Alto, knocking out power to all the city's 28,000 customers, including schools and the local Stanford Hospital, which is operating on backup power.

Residents are being asked to conserve water, which is pumped to customers with the help of electricity.  We'll be sure to keep you informed on the latest details of this horrible incident. A bus has been brought to the Tesla facilities to pick up employees who are "shaken" by the incident.

Our hearts go out to the families involved.

More reports from Wired, Motor Authority, Jalopnik and Olark.