Police don't believe a bomb threat at Hewlett Packard's offices that forced employees to stay inside in Palo Alto Wednesday afternoon is credible, but continued to search the building into the evening, a spokesman said.

Around 2:50 p.m., Palo Alto police dispatch took a call from a person who made a bomb threat targeting HP, police Capt. Zach Perron said.

Police quickly contacted the company's security personnel, who were unaware of the threat and worked with responding officers to search the Hewlett Packard Enterprise site at 3000 Hanover St., Perron said.

The company decided to keep their employees inside until the search outside was completed, Perron said.

Multiple search teams canvassed the parking lots and vehicles sitting outside to make sure there were no suspicious devices or people, Perron said.

The building was secure and no one was evacuated, according to police. Two police cars were seen outside one of HP.

As a precaution, Page Mill Road was blocked between Hanover Street and Peter Coutts Road from about 3:30 p.m. until 4:45 p.m., police said on Twitter.

Police determined the call lacked credibility but will continue searching for anything suspicious in the now-empty building with four bomb-sniffing dogs, one from Stanford University's Department of Public Safety and three from the Santa Clara County Sheriff's Office, that will last into the evening, Perron said.

HP employees told the Weekly they were given little information about the investigation but were allowed to leave once the all-clear was given.

The company's crisis management team told employees to remain indoors during the investigation, according to one employee in his 20s who declined to give his name.

No additional buildings were affected by the threat, according to police.

The entrance to HP Enterprise's offices at Peter Coutts Road and security gate remained closed shortly before 5:30 p.m.

William Mead, a limo driver for Lux Bus America, was waiting outside the company's offices for more than an hour to pick up a group of people visiting from Denmark he had dropped off in the morning.

Stanford University journalism professor Cheryl Phillips was biking home around 3:30 p.m. when she saw two police officers blocking Page Mill at Hanover and a third officer farther down on Hanover. Traffic didn't appear to clogged up by the closure at the time.

Phillips said she saw people still waiting at bus stops within the blocked-off area.

DXC Technology Company and Lucile Packard Children's Hospital Stanford offices are a few of the many companies in the area.

The Santa Clara Valley Transportation Authority's bus lines 101, 102, 103 and 89 were rerouted during the police investigation, the agency said in an alert.

This story will be updated as more information becomes available.