VACAVILLE, Nov. 13 — Convicted mass murderer Charles Manson faces felony drug possession charges stemming from a cache of marijuana found in his cell, but prison officials ruled out filing escape charges against him in connection with a recent incident.

Lt. Don Custard, a spokesman for the California Medical Facility, a prison housing 2,750 inmates 50 miles east of San Francisco, said prison laboratory tests showed the marijuana was among contraband material found in Manson’s cell on Oct. 29.

Subsequent searches of areas of the prison to which Manson had access turned up a catalogue showing how to order hot-air balloons, Custard said.

The test results have been turned over to the state attorney general’s office who will decide whether to prosecute, Custard said.

“The whole thing is over with,” Custard said. “All this institution has charged him with is marijuana possession.” The amount of the marijuana was not disclosed.

“The attorney general’s office will decide whether to pursue felony charges,” he added.

Manson, 47, mastermind of the 1969 Tate-LaBianca slayings, was removed from the main prison population and has been kept in isolation since Oct. 29, when a guard discovered him and three other inmates in the prison chapel.

Later a search of an attic above the chapel turned up a tape recorder, a tobacco pipe, a vial containing an unidentified white liquid, pieces of metal, tin snips and sandpaper.

A search of Manson’s cell turned up the marijuana, while still another search of the chapel disclosed more marijuana, a tube filled with flammable liquid, 100 feet of nylon rope, the catalogue on hot-air balloons and keys that Custard said did not open any security doors.

Manson is serving multiple life sentences.