CHICAGO — Accused murderers, robbers and rapists in Cook County Jail’s oldest maximum-security complex often use toothpaste caps and toilet paper to jam their cell doors and sneak out.

Sometimes, they don’t even need to resort to such tricks. The aging locks in the doors malfunction on their own.

“Some of them are so bad they can literally slide the door, give the door a little jiggle, and it will slide open,” a Cook County sheriff’s correctional officer said.

Between February 2007 and last May, there have been at least 288 problems with jail doors in the 608-cell complex called Division 1, a Chicago Sun-Times/Better Government Association investigation has found.

A Cook County sheriff’s spot check about a year ago showed that 69 cell doors in the division — more than 11 percent — were “found to be not closing properly, with the potential for being breached,” records show.

Those doors have been fixed, officials said. But problems continue. And they aren’t limited to cell doors. County records show stairwell, corridor and tunnel doors have been malfunctioning, too — though not with the same frequency as cell doors.

“It’s Jail 101: The doors ought to lock,” said Charles Fasano of the John Howard Association, a watchdog group that monitors the jail under a federal court order.

County officials said they’re trying to fix the problem through repairs and a new security strategy. Division 1, which opened in 1929, is unique because its cell doors slide open, rather than swinging on hinges like the 3,168 cells in the jail’s other 10 divisions.

“Guys have figured out that using a cap from a tube of toothpaste with a piece of paper” can keep cell doors open while making it “look like they’re locked on the [electronic] panel,” Fasano said.

The concern isn’t so much about inmates escaping — they would need to go through three more sets of locked doors before they would even reach a hallway — but about gang fights. In August, rival gang members in Division 1 left their cells and began stabbing each other with homemade knives.

Inmates told sheriff’s investigators the correctional officer on duty pushed a button to unlock all the cell doors at the same time, an error that led to the melee. But the officer insisted he didn’t open the locked doors simultaneously and that the inmates must have done it on their own.

Another officer, as well as an inmate involved in the fight, told the Sun-Times that malfunctioning doors contributed to the problems then.

Of the 288 reports of door malfunctions, 245 involved cell doors. They included 129 reports of cell doors not locking, being off-track or otherwise “broken.” Another 112 involved problems with electronic panels and switches that control the doors.

A few years ago, similar problems surfaced in the jail’s other maximum-security complex, Division 9, Fasano said. In one case, in February 2006, correctional officers were doing an inspection when they found a cell door open and a playing card jammed in the lock, according to a sheriff’s office report. An inmate in the cell got combative when questioned and punched one of the officers in the face.

In August, the sheriff’s office launched a new security strategy to deal with faulty doors. Correctional officers must now double-check a panel that tells them whether cells are open or locked. And they go cell-to-cell to check, sheriff’s spokesman Steve Patterson said.

Last year, the county spent more than $70,000 to fix more than 70 doors in Division 1.

A $350,000 contract is pending to replace worn-out parts in the locks in another 533 cells, said James D’Amico, director of the county’s Facilities Management Department.

In the last four years, Cook County Sheriff Tom Dart, who runs the jail, has gotten about $4.5 million from the county for door and frame replacements in Divisions 4, 5, 6, 9 and 10, Patterson said.

“The sheriff is, in a sense, a tenant, and the County Board president is the landlord,” Patterson said. “We have absolutely no control of the maintenance of the facility. It’s a strange setup — and one the sheriff is not happy about.”

D’Amico meets once a week with sheriff’s officials about door repairs that are needed. He said his staff is doing its best despite having a budget that’s been slashed from $3.5 million to $1.5 million since 2003 and a staff that’s gone from 470 to 370 over the same period.

A federal judge overseeing jail conditions has ordered the county to hire more facilities management staff but has not said how many yet, D’Amico said.

The same judge has ordered Dart to hire more than 200 correctional officers to bolster jail security.