WATCH: 'There's A Bear In The School, There's A Bear In The School!'

EUREKA, Mo. (CBS Local) -- A small black bear who got trapped inside a Catholic church and school in Missouri was tranquilized and removed Tuesday, authorities said.

Video posted on Facebook by Eureka, Missouri Community showed the male bear, weighing about 90 pounds, trying to get out of Most Sacred Heart Parish in Eureka.

The Parish was founded in 1889 as a Catholic Church and now includes an elementary school. Classes was out for the summer, so no kids were present at the time.

The pastor, Father Joe Kempf, said the bear wandered inside the building early Tuesday through a door that was propped open.

"The principal calls, kind of breathless: 'There's a bear in the school, there's a bear in the school!" he told CBS affiliate KMOV. "Now we have all these security lock-down drills and all these facilities secure things, which we do very well -- I thought she forget the safe word. I thought there was an intruder. She goes, 'It's really a bear.' I go, 'This is really awesome!'"

Officials initially tried to lure the bear out of the school, but he wouldn't budge. The bear was then tranquilized and taken to a heavily-wooded area away from homes and businesses, according to the Missouri Department of Conservation.

Before he entered the church, the bear had been spotted in the streets and alleys of Eureka. Surveillance video showed just how close the bear got to people.

"My first instinct was to try to help him, but he was gone too fast," Melonie Johnson, an employee of Urethane Roller Specialists, told KTVI.

Conservation officials said the bear appeared to be 18 months old, an age when bears are often pushed out of the den their parents to make room for young cubs.