When fellow officers discovered Chicago’s police chief asleep behind the wheel of his running SUV, they did not conduct any sobriety tests and let their boss drive home – a decision that has thrown a spotlight on what happens when one officer confronts another on patrol.

Many details of that mid-October encounter are still unclear. But the incident led Mayor Lori Lightfoot to fire Superintendent Eddie Johnson, and it could lead to discipline for the officers who were there.

When it comes to police pulling over police, the unwritten rule has long been one of professional courtesy: Don’t call attention to the incident over the radio and maybe offer a ride home, particularly if no one else is involved. But that practice has been increasingly called into question, amid calls for better police accountability and expanded use of body cameras. Police argue that they use similar discretion with ordinary citizens, but critics say officers often get a pass and protect their own at all costs.

For officers, pulling over a fellow cop can be an awkward dilemma, one that’s magnified when it’s the head of one of the nation’s largest police departments.

“It’s a worst-nightmare situation for a police officer to encounter their superior or chief who has been drinking,” said Philip Stinson, a criminal justice professor at Bowling Green State University in Ohio. “They’re damned if they do, and they’re damned if they don’t in terms of how they respond or act.’’

On one hand, there’s the fear of retaliation for speaking out. On the other, there’s possible punishment for engaging in a cover-up.

Officers responding to a 911 call found Johnson slumped behind the wheel of his car not far from his South Side home early on Oct. 17. Local reports say he reportedly displayed his badge and waved the responding officers off. Johnson initially blamed an issue with blood pressure medication, but has since apologized for a lapse of judgement without elaborating. He also told Lightfoot he had a couple of drinks with dinner earlier that evening.

An investigation into Johnson’s actions, which has reportedly extended to other officers, is ongoing.

Police argue they have a discretionary power and that similar thinking is used when they encounter other motorists, like giving a grandmother a pass for running a stop sign or offering a warning. When it comes to the boss, there’s particular sensitivity.

’’The officer on the scene is the only one who knows the right thing to do,” said former Chicago police Lt. Robert Weisskopf. “He doesn’t have to enforce every law to the utmost degree, that’s a robot.”

In Johnson’s case, he had well-known medical problems, Weisskopf said. The former superintendent, who was set to retire at the end of the year, underwent a kidney transplant and had been hospitalized for a blood clot, factors a responding officer would already know.

But not everyone is buying it.

Lightfoot, a former federal prosecutor whose campaign promises included police reform, said firing Johnson sent a message about changing the culture in the department, which like other law enforcement agencies has a code of silence.

“Perhaps in years past, someone in Mr. Johnson’s circumstances would have been allowed to simply retire,” Lightfoot said. “The old Chicago way must give way to the new reality.”

Still, there’s no agreement on exactly what officers should do. Like most policies for the nation’s 18,000 police departments, there’s no standard practice.

Michael Scott, an Arizona State University criminology and criminal justice professor, said most departments with criteria would request that a supervisor be contacted or sent to the scene.

The increase in the use of video, through body cameras and dashcams, has also complicated things. Cameras make officers less likely to give people a pass, but they can also be easily turned off.

“As policing has become increasingly public, and as the public becomes less trusting of the police,” officers have moved “toward less informal resolution of incidents like this and toward a more formal resolution,″ said Scott, a former police chief.

Some police departments have addressed the issue head-on.

Denver police state in their 776-page police manual that “whenever it becomes likely that probable cause exists to arrest or to file charges” against a fellow officer or firefighter, internal affairs must be “notified immediately.″ The department came under fire in 2011 when an independent monitor suggested that Denver police do not arrest fellow officers for drunken driving unless they are involved in crashes.

A rulebook for Chicago officers does not spell out the issue specifically, and a police spokesman did not return messages seeking comment.

Charles Wexler, executive director of the Police Executive Research Forum, said officers should treat everyone they pull over the same, but the situation is always complicated when it’s a fellow officer.

“These are no win situations,” he said.

(AP)