Police have taken a person into custody related to a fire Friday night on the city's south side.

According to Madison Fire Department spokesman Joel Kneifel, fire crews were called to an office building at 2601 West Beltline Highway around 8:45 p.m. for a report of a small fire. When crews arrived, they found the fire had been extinguished by the building's sprinklers.

Madison police had reported seeing smoke in a fifth-floor room as officers searched for a person inside the building causing damage, according to a news release.

Kneifel said the fire mainly affected the fifth floor and was possibly caused by a suspicious item on the sixth floor.

Police found a person in the building at the time of the fire who they believe may have been involved in the incident and took that individual into custody. Kneifel said it's possible that person's actions are related to the fire.

Fire investigators were still looking into the cause of the fire Saturday. There was extensive damage to electronic and computer equipment used by the multiple businesses in the building, the fire department said.

Fire officials didn't have a total estimate of the cost of damage, but said it may be more than $100,000.

The fire was under control at 9:07 p.m., the fire department said. The scene was cleared around 10:30 p.m.