A joint investigation involving law enforcement agencies in King and Pierce counties had led to the arrest April 6 of a 49-year-old man suspected of robbing 10 banks in King and Pierce counties.

The heists numbered two banks on the day Stewart Gordon Robertson was arrested — one in Puyallup and the second in Summit about 8 miles away.

On April 7, the Pierce County Prosecutor charged Robertson with six counts of first-degree robbery and two counts of attempted first-degree robbery, to which he entered a plea of not guilty. His bail was set at $250,000. His next court appearance is May 5.

Undercover Pierce County Sheriff’s Department deputies and a Puyallup police officer made the arrest, capping an investigation between Pierce County, Auburn, Des Moines and Milton police departments.

According to a release, after Robertson’s arrest, he admitted to robbing four banks in King County and six in Pierce County, including three banks in Auburn.

According to the release, Robertson pulled his first robbery of April 6 at about 1 p.m. in the 700 block of Shaw Road East in Sumner. Afterward, undercover deputies started looking for his vehicle in the South Hill area. According to the release, deputies were familiar with Robertson’s car because law enforcement was already investigating him for other bank robberies.

Then at about 2:30 p.m., deputies said, Robertson robbed his second bank of the day,, this time in the 11500 block of Canyon Road East. Minutes after the second robbery, undercover deputies saw his vehicle and stopped it with the help of a Puyallup police officer. Robertson was taken into custody in the 3900 block of South Meridian Avenue in Puyallup.

Deputies did not disclose how much money was taken.