Police responded after an alleged fight that started at Trident Bar and Grill, 2033 E. Speedway Blvd., continued at the Phi Gamma Delta fraternity house, 1801 E. First St., at 5:10 p.m. Saturday.

A group of men outside the house flagged down police and told them what happened at the bar. They said two men stepped outside and began “”facing off,”” according to reports.

One of the men punched the other in the cheek, then ran with his two friends to the fraternity house.

The victim got up and decided to chase the man; some bystanders followed because they did not agree with the assailant’s actions. The assailant entered the house through a door on the east side of the house.

When the bystanders went inside the house to confront the assailant, they were met by several men who told them they were trespassing and had to leave.

The bystanders gave officers a description of the assailant.

Police searched the house but could not find anyone who matched the description.

The fraternity’s vice president said the assailant and his friends were not associated with the fraternity and had left the house through another door prior to the officers’ arrival.

Police have yet to find the assailant.

Police broke up a fight between 10 members of Delta Chi fraternity and one former member of the fraternity at the intersection of East First Street and North Cherry Avenue at 11:39 p.m. Friday.

Outside of the Delta Chi house, 1701 E. First St., an officer found a man on the front porch yelling at members of the house, who were inside.

The man said that he had been assaulted after a prank went badly, but added that he did not want to get anyone in trouble or press charges.

The fraternity’s president told the officer the man had attempted to commit an annual prank against the fraternity that involves alumni members setting the Delta Chi Homecoming float on fire.

The president said he did not want to press charges and only wanted the man removed. The man was escorted off the property and told he could be arrested if found on Delta Chi property.

The man was deferred to the Dean of Students Office for fighting.

Police responded to the Life Sciences South building, 1007 E. Lowell St., because of a small fire in a lab Friday.

When an officer arrived, the building had been evacuated. Someone on the fifth floor had pulled the fire alarm after hearing someone else announce a fire.

The woman who caused the fire told the officer she was conducting an experiment with a Bunsen burner.

After she heated up a jar containing ethanol, she heard a pop and saw flames coming out of the jar. She reached for a plastic spray bottle to douse the flames, but the fire grew larger and caught the bottle on fire. She tried to run out of the room with the flaming bottle, but the plastic started melting and dripped onto a mop, which caught fire.

Another student used a chemical fire extinguisher to put out the flames, and everyone exited the building.

The woman showed the officer her middle finger, which was burned and blistered.

The officer went into the lab and saw no smoke or active fire.

The Tucson Fire Department investigated the lab and said there was no chance for re-ignition.

Police are looking for whoever damaged the Nate’s hot-dog cart in front of the Harvill building, 1103 E. Second St., sometime Thursday evening or Friday morning.

A cart employee told his supervisor that when he locked up the cart on Thursday, everything was fine. The next morning, the employee noticed a broken window on the cart and overturned concrete seats nearby.

The cart is UA property.

Police noticed the cart’s window had been pushed inward, and that the glass was severely cracked but still in one piece.

Police Beat is compiled from official University of Arizona Police Department reports. A complete list of UAPD activity can be found at http://www.uapd.arizona.edu.