Police responding to a burglar alarm found an open door but no intruder inside a Butler home Friday.

City officers, however, found something else — seven marijuana plants.

Police on Tuesday filed felony and other drug charges against husband and wife — Leon Lewis and Altovise T. Lewis, both 33 — who rent the two-story house in the 400 block of Mitchell Avenue.

Officers were sent to the home about 9:30 a.m. Friday after the security company that monitors it notified police that a burglar alarm had been tripped there, according to court documents.

Police found a back door had been forced open. Officers went inside to search for anyone in the house. They found no one.

But they happened upon what appeared to be a marijuana grow operation in the basement, documents said.

Police left the house long enough to allow officer Michael Tresky time to obtain a search warrant.

In addition to the plants, documents said, the basement search turned up grow lights, timers, potting soil, plant food, a power supply and fan — tools of the grow-op trade.

Additionally, police said they found scales and spoons with suspected drug residue and crack cocaine drug packaging materials in the kitchen.

More drug contraband was found in one of the bedrooms of the house which, police noted in court papers, is within 1,000 feet of the Broad Street Elementary School.

Leon Lewis and Altovise Lewis are charged with possession with intent to deliver a controlled substance and conspiracy, both felonies, and misdemeanor counts of possession of a controlled substance and drug paraphernalia.