Evening update: Pitt’s chapter of the ACLU is co-sponsoring an Oakland Unites for First Amendment Rights rally on campus tomorrow at 5:30 pm. A four-point petition will be circulating at the rally — we’ll post the text as soon as we get it.

Last week’s G-20 meeting of the leaders of the world’s 20 largest economies drew massive protests in and around the University of Pittsburgh, and now police and campus administrators are facing heavy criticism for their handling of the incidents.

Over the course of the two-day meeting, police used sonic cannons, tear gas, pepper spray, bean-bag projectiles, smoke canisters, stun grenades, and rubber bullets on demonstrators, making hundreds of arrests. Innocent students, including some student journalists, were caught up in police sweeps on the Pitt campus.

Police arrested nearly two hundred people during the course of the G-20 demonstrations, including more than fifty students. The Allegheny County district attorney has already announced that charges against four students will be dropped, and more dismissals are expected.

Update: In a reversal of a policy announced yesterday, Pitt will allow students seeking dismissal of charges to bring attorneys to their meetings with campus police officials. The university has also confirmed that no campus judicial proceedings will be brought against students whose criminal charges are dismissed.

Dozens of videos from the protests have surfaced online, ranging from the hilarious (three burly cops in face masks attempt to pass as protesters, and failing spectacularly) to the chilling (students trapped on a stairway between two sets of cops, each trying to force them to go the other way).

Two student journalists for the Pitt News were arrested while covering the Friday night protests, and eight more were tear gassed, pepper sprayed, or maced. Stories have also emerged of students being locked out of their dorms, then arrested for failing to return to their rooms.

One student has posted a lengthy account online of how she was arrested for “failing to disperse” while helping students to disperse by holding open the locked doors of one dorm building. She describes students being arrested as they entered the dorms, and other reports suggest that students were arrested while waiting in line at local restaurants, or studying in the campus library.

Violations of students’ rights on campus were not limited to arrests. One video posted online shows police lobbing a tear gas canister onto the balcony of a dorm from which a group of students were quietly watching the protest in the street below. (The canister is thrown just after the two-minute mark in the video.)

The question of what limits should have been set on the actions of municipal police on the Pitt campus is being raised over and over again in the aftermath of the G-20, and evidence is emerging that it was a subject of dispute among police at the time. Police scanner recordings obtained by the Pitt News show that a high-ranking Pitt university police officer intervened personally on Friday night to prevent a non-university police “attack team” from storming the Towers, a campus dorm.

Adding to the confusion, and contributing to the police overreaction, is the fact that Pitt’s campus is an urban one, with no clear boundaries, and and the fact that thepolice were brought in for the G-20 protests from as far away as Tucson, Arizona. Many of the cops present were unfamiliar with the location.

Pitt’s university police have also been criticized, however. The university’s text message based Emergency Notification System was not used at all on Thursday, and only two messages were sent out on Friday — one encouraging them to “be careful” and “exercise good judgment,” and the other advising them to “remain near their residences.” As noted above, a number of students were ultimately arrested at or near their dorms that night.

Pressure on the police and the Pitt administration has been building since the meeting ended, with many claiming that, as one online petition puts it, “the right of citizens — students, professors, families, community members, and media — to assemble and gather peacefully in public was not only denied and violated but suppressed with unnecessary and excessive force.”

Note: Check out What Happened At Pitt?!?! for a huge collection of links and resources.