The Baltimore Police Department is taking steps to begin videotaping interrogations in its most serious criminal investigations — a long-resisted move that is being adopted by an increasing number of Maryland law-enforcement agencies.

The department, the eighth-largest in the country, recently began using video as part of a series of reforms of its sex-offense unit. Now officials are exploring equipment options and the policy impact of videotaping homicide and shooting interrogations. Detectives are being trained on subtleties such as where to stand and how their demeanor will play to a jury.

"I'm committed to doing this, and I have a bunch of really smart guys working on getting this done," said police CommissionerFrederick H. Bealefeld III, who has studied videotaping since he was chief of detectives. "But it's not as simple as going to Radio Shack and bolting a camera into the wall."

Since 2008, when the General Assembly endorsed videotaped interrogations as a preferred policy in Maryland — but did not require them — the number of agencies with audio and visual recording has increased from 26 to 42, including all of the Baltimore region's largest departments. An additional 17 agencies have plans to purchase new equipment in the next two years.

"The technology has changed tremendously," said Kristen Mahoney, director of the Governor's Office of Crime Control and Prevention, which has provided $152,000 in grants for video upgrades. "A few years ago, we were looking at costs of [$8 million to $9 million] to hard-wire an interrogation room."

While the public is accustomed to watching police interviews on reality shows such as "The First 48," the practice wasn't widespread until recently. And city officials say there are major logistical concerns about reliably archiving what could be thousands of interviews a year.

Hundreds of jurisdictions across the country now videotape interrogations, and it is required by law in several states and the District of Columbia. The shift has been spurred by increasing affordability, as well as by questions of coercion and false confessions as DNA testing has led to the release of scores of inmates.

In Harford County, the sheriff's department says it has long recorded interviews in major cases and recently got funding to add interrogation rooms to neighborhood precincts.

"It's pretty much a standard for progressive law-enforcement agencies," Sheriff L. Jesse Bane said. "People are finding out that the things Hollywood portrays really don't take place."

Bladensburg police Chief Charles Owens sees video as "just another step in logging evidence." His officers use it for all suspect interrogations, for misdemeanors and felonies, and said it turns many cases into a "slam dunk."

In a recent case, a suspect accused of burglarizing several homes and sexually assaulting a woman gave a confession that was recorded. At trial, he tried to claim his confession had been coerced, but "the audio and video clearly showed that it was voluntary," Owens said.

Currently, detectives in Baltimore interview a suspect and take notes. When a suspect is ready to give a statement — or, critics say, when a detective is ready for them to give a statement — detectives begin audio recording. That has led to accusations over the years that statements are crafted during untaped interrogation sessions.

At the recent trial of a man charged with killing a teenage boy and stuffing his body in a closet, defense attorney Bridget Shepherd told jurors that witnesses and suspects were tormented, comparing it to "Guantanamo Bay" and saying her client's taped confession didn't give the full story.

"How do these statements come about?" Shepherd asked the jury. "I suggest that when they began the interrogation, he told the truth. … But it wasn't the statement police wanted — it didn't match the theory they had in their mind."

Elizabeth Julian, who oversees the Baltimore public defender's office, said her attorneys are "always suspicious about what goes on" during interrogations and support a move toward videotaped recordings.

"If everybody is in the pursuit of justice, it will be a better window into the process for everyone," Julian said.

The move also has the support of the Baltimore state's attorney's office. Deputy State's Attorney Elizabeth Embry said prosecutors are talking with police about crafting policies on recording. She was involved in efforts to implement video in interviews with victims of sex offenses, part of a series of reforms aimed at improving investigations.

Baltimore County has long taped interviews, providing, for example, a dramatic account of Cockeysville teenager Nicholas Browning as he shifted from lying about killing his parents and younger siblings to explaining how he methodically carried out the crime.

A recorded interview was also used by Baltimore County prosecutors to seek the death penalty in a recent murder-for-hire case, though the jury ultimately rejected that punishment. The state's capital punishment law now requires DNA or other biological evidence, or a video recording that "conclusively" links the defendant to the killing.