But they are looking for more suspects and they need the public's help.
Surveillance photos of the robbers were released. Police said in each case the suspects walked into the clinic posing as customers, then showed the clerk a handgun and demanded money. In some cases, the suspects fired shots.
In one case a clerk was struck in the back. The suspects then left in several vehicles.
In most cases they get away with tens of thousands of dollars in cash and large quantities of marijuana which they later sell on the streets.
"In some instances they've pistol whipped employees," explained Deputy Chief Michael Moore, LAPD. "In the one on the 23rd of May their actions required one of those employees to be hospitalized. In that robbery a large amount of marijuana and cash was taken and the suspects fled in two different vehicles: a silver four door Honda Accord that has a sunroof on it and the second one being a silver two door Mercedes coupe."
Police said that the suspect in custody was seen in the released surveillance video.
The suspect is 20-year-old Nicholas Bradford Brown but they are looking for at least two other young males between 18 and 30 years old.
Police say these suspects are considered armed and dangerous.
The police also said that it appears to be the new crime trend. They say in the West San Fernando Valley there are at least a hundred medical marijuana dispensaries and that in the past year, each of those dispensaries had been robbed or burglarized at least twice.
If you have any information in these robberies you are asked to call 1-877-527-3247.