SANTA CRUZ, Calif. -

Santa Cruz County deputies said medical marijuana drove 21-year-old Vincent Turner to rob someone at gunpoint in December.  Deputies said Turner and the victim agreed to meet up in the parking lot at Dominican Hospital through a Craigslist ad.  This isn't a one time thing for Turner. Investigators said he's linked to another case in Elk Grove, Calif.

Deputies think there may be more Craigslist victims out there who may be afraid to come forward.  We found out why having or selling medical marijuana could make you vulnerable to crime.

"At any time a person is subject to crime. But and to think about it in terms of a more desperate (situation), people become (more so) because of poverty and because of illness,” said Valerie Corral, director of The Wo/Men's Alliance for Medical Marijuana or WAMM in Santa Cruz.

Corral said she's in charge the longest-running medical marijuana collaborative in the nation.  She said WAMM takes patients through every step of life as it relates to dealing with illness and being open about treatment isn't easy for everyone.

"People can provide medical marijuana for individuals with a doctor's recommendation. There's supposed to be a collective, there's supposed to be some oversight," Corral said.

Corral said oversight could protect some who chose to advertise medical marijuana online.  California NORML, a non-profit dedicated to reforming California's marijuana laws, said on its website that selling online isn't safe.  But local police told us it's legal as long as the seller verifies the customer's medical marijuana card.

Corral said she's worked with lawmakers to develop better laws to make medical marijuana more accessible.  She hopes one day the stigma of needing to do business behind closed doors would become a thing of the past.

"It’s nebulous because really in the beginning, decades ago, we had the opportunity to create something so amazing where we governed ourselves and didn't become the tools of greed," Corral said.