A Portland Timbers fan and an FC Dallas supporter were involved in an altercation inside Toyota Stadium during the first half of Saturday's match between the Timbers and FC Dallas.

Multiple Timbers fans present at the game said that a Dallas supporter, who was upset by what he interpreted as vulgar cheers coming from the Portland fans, approached a Timbers fan in section 119 during the first half.

Things allegedly got violent after the Dallas fan angrily asked the Timbers fan to stop the group from using vulgar chants. Multiple Timbers fans said that the Dallas fan head butted the Portland fan and that the Portland fan responded in self-defense by punching the Dallas fan.

"I was in the middle of it and I broke the fight up," said Jonathan McCauley, co-founder of the Lone Star Brigade, a group of Timbers supporters based in Texas. "Once the guy became more aggressive, (the Timbers fan) acted in self-defense."

But video footage may not back up what Timbers fans have reported.

FC Dallas released a statement Monday indicating that police had viewed a video of the incident and were pursuing a criminal case against a Timbers supporter.

The statement read, “Violence of any kind is not tolerated at Toyota Stadium. The incident in question was reported to police and it will be filed as a criminal case. The confrontation was also captured on video. Police viewed the video and are moving forward with a criminal case against a visiting supporter. Due to the ongoing investigation, FC Dallas is unable to comment further on the incident.”

Members of the Lone Star Brigade were also troubled by two other incidents that occurred Saturday.

At the end of the match, Timbers supporters noticed that two of their flags had been stolen from the bottom of section 119. According to a statement from FC Dallas, one of the flags was “immediately recovered by security, but the second made it up to the concourse level and out the gate. The second banner was not able to be recovered.”

Every fan that had attended a match with the Lone Star Brigade over the last few years had signed the flag that security was unable to recover, said Dan Crawford, 44, a member of the Lone Star Brigade.

After the Portland fans left the stadium and were waiting by the buses for the Timbers players to leave, another Dallas fan came up to a Timbers fan and stole his scarves, multiple Timbers fans said.

According to FC Dallas representatives, security pursued the offender and recovered the scarves.

McCauley said that members of the Lone Star Brigade would be sending a letter of complaint to FC Dallas.

“The group was a little shook up,” McCauley said. “It’s definitely something in my four years of being a leader in this group that I’ve never witnessed before.”

-- Jamie Goldberg | @jamiebgoldberg