An animal shelter in Vallejo was hit with a string of overnight burglaries multiple times in the last two weeks, according to staff.

The Humane Society of the North Bay, located on Sonoma Boulevard in an industrial area of south Vallejo, has been burglarized four times since Oct. 25 by at least one individual who broke into multiple storage sheds and may have stayed in one storage shed overnight, possibly using injectable drugs.

Most recently, the shelter was broken into both Monday and Tuesday nights. No animals appeared to be harmed in the burglaries.

According to Joseph Hayden, the organization’s board president, the person or persons stole medical equipment for a spay and neuter clinic, including a surgical table, an industrial wagon and a pop-up tent.

The shelter’s front gate was also broken, leaving the organization vulnerable to more break-ins as leaders scramble to fundraise to cover the cost of fixing multiple locks and doors.

Hypodermic needles set aside for the clinic were also apparently used during the break-in and left behind, Hayden said.

Hayden estimated that losses from the burglary amounted to around $20,000. At this time, police do not have any leads on who is responsible for the burglaries, he said.

The shelter is a nonprofit, independent organization that relies mostly on donations, according to Hayden. There are currently around 40 cats and 20 big dogs at the shelter, and an equal amount in foster homes but supported by shelter resources.

Hayden said that coming to work every morning was scary for staffers, and the animals clearly were distraught after the nighttime visits.

He said, “It’s very unnerving to walk in, not knowing if the gate is even going to be open, wondering, ‘Is the person still here?’”

“We don’t have any resources,” said Hayden. “To keep our lights on, we have to fundraise for most of the cost of medical care for the animals, many of which are brought to us emaciated and abused.”

A formal fundraising campaign has not been set up, but the organization is accepting donations at their website.

Vallejo police did not immediately respond to requests for comment on the break-ins.