MILLBRAE (CBS SF) – The San Mateo County Sheriff’s Department is investigating an early morning home invasion robbery Sunday where three armed suspects tied victims up and demanded valuables, according to authorities.

San Mateo County Sheriff’s Deputies responded to a report of a home invasion robbery at a residence on Toyon Drive on Sunday, September 23, just after 12 a.m.

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Prior to deputies arriving at the scene, the suspects fled in a U-Haul truck in an unknown direction.

Investigation determined three adult males wearing ski masks and armed with handguns entered the home. Once inside, they confronted the victims, tied them up and demanded valuables.

The suspects left the scene with an undetermined amount of money, ammunition, tobacco and two safes.

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One of the victims suffered injuries to her head from being struck by a suspect.

Sheriff’s detectives said they have reason to believe the incident was not random and that the home was specifically targeted.

The Sheriff’s Department warned the community at large in the area to remain vigilant, but said there was no indication that the suspects would be a threat to the general public.

Residents were advised to always secure doors, windows, garage doors and side gates.

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Anyone with information about the home invasion robbery was asked to contact Sheriff’s Detective Cosens at (650) 363-4347 or Anonymous tips can be left by calling the San Mateo County Sheriff’s anonymous tip line at 1-800-547-2700.