LIVERMORE — Tensions between police and medical marijuana advocates escalated this week with the arrest of four men in a pot collective in Livermore after they returned from a cannabis trade show in San Francisco.

Some 60 supporters of the men rallied outside a Pleasanton courthouse Wednesday afternoon shortly before the defendants were charged with conspiring to illegally grow and sell marijuana.

“The city of Livermore is unfairly targeting people who are providing medical marijuana to patients,” said Ray Ahmed, former owner of the Tree of Life, a Livermore cannabis storefront that closed in 2015 after a raid by police. “They are blocking treatment of patients.”

He and others at the rally contend Livermore is going overboard in its hard line against medical marijuana.

Alameda County prosecutors and Livermore police see it differently. The District Attorney’s Office filed felony criminal charges Wednesday against the men, including Chris Phillips of Livermore. An outspoken medical marijuana advocate, he has had previous runs with police over marijuana, and he used to run a cannabis delivery service that closed after a raid on his home.

Bail was set at $250,000 for each by Alameda County Supervisor Court Judge Jacob Blea III. Three of them remain in custody; a fourth is expected to turn himself in on Friday.

Prosecutors say Phillips is the chief executive officer of Dabbenport Extracts, which concentrates marijuana, and the other three defendants are associated with the business.

The four men attended the High Times cannabis trade show Saturday and Sunday at the Cow Palace in San Francisco.

Chris Phillip’s brother, Joseph Phillips, said he was arrested Sunday night in Livermore shortly after he got off the freeway on his way back from the show.

Prior to the court hearing, Joseph Phillips said Dabbenport is legally helping get pot to people who need to relieve pain for a variety of ailments.

Livermore police, in papers filed in court, said they stopped Joseph Phillips Sunday shortly before midnight and found 1,180 individual packages each containing between 1 and 1.5 grams of concentrated cannabis.

A few hours later on Monday morning, police arrested Chris Phillips, Cameron Zalaha and Jacob Soutsos following a raid at Chris Phillips home where police say they found 46 marijuana plants in the backyard.

During the rally Wednesday, Mike “Grand Daddy” Grafton, a marijuana advocate, said he believes Livermore targeted Chris Phillips because he has been outspoken in defending rights of patients to use medical marijuana.

Contact Denis Cuff at 925-943-8267. Follow him at Twitter.com/deniscuff or facebook.com/denis.cuff.