The Baltimore City Detention Center is seen earlier this year in Baltimore following the arrest of several corrections officers. (Michael S. Williamson/The Washington Post)

Fourteen current or former Maryland corrections officers were arrested Thursday, accused of aiding members of a violent prison gang, the latest development in a sweeping corruption investigation at two state-run detention facilities.

A federal grand jury indictment unsealed Thursday charges the prison guards with racketeering and drug- and money-laundering conspiracies. Officers allegedly smuggled cellphones inside of sub sandwiches and Percocet pills in their underwear. One estimated making as much as $15,000 in one week.

The inmates have control over the corrections officers, “the very people who are charged with maintaining order over the prison population,” according to an FBI affidavit for a search warrant.

The indictment follows the arrests of 13 corrections officers and leaders of the Black Guerrilla Family gang at the Baltimore City Detention Center and the Baltimore Central Booking and Intake Center during the spring. The gang leader at the center of the initial case also impregnated four of the prison guards.

The unsealed court papers provide a fuller picture of the extent of the alleged bribery and smuggling operations at the detention facilities in addition to the personal relationships between guards and inmates. A former corrections officer authorities interviewed in July estimated that 75 percent of the guards at the detention center engage in smuggling.

More Post coverage of the Maryland jail scandal.

The alleged illegal activity described in the latest indictment occurred before the arrests in the spring, according to Maryland U.S. Attorney Rod J. Rosenstein. The initial case prompted criticism of the Maryland prison system’s oversight of inmates.

Since then, prison officials have replaced top leadership at the detention center, created an anti-corruption investigative team and imposed tougher screening procedures for inmates, employers and visitors.

“So long as we continue to make our prisons and jails safer, so long as we continue to improve the integrity of these institutions, you’ll likely see more arrests rather than fewer,” Gov. Martin O’Malley (D) told reporters Thursday after a forum to discuss progress on crime during his administration.

In court papers, federal officials renewed their criticism of the state’s disciplinary process for corrections officers. The system was overhauled three years ago, with O’Malley’s backing, giving officers the right to appeal certain punishments to a board of their peers.

One of the guards arrested Thursday — Ricolle Hall of Glen Burnie — was a member of the three-person board in Baltimore from 2011 to 2013.

It is “well-known to [corrections officers] that it is very unlikely that they will be fired or severely disciplined for smuggling contraband or fraternizing with inmates,” according to the affidavit. The system set up by the so-called Correctional Officers’ Bill of Rights is “ineffective as a deterrent to [corrections officers] smuggling contraband or getting sexually involved with BGF gang members.”

O’Malley told reporters Thursday that he was not aware of any instance in which the bill of rights has prevented a successful prosecution of an officer. Still, “there may be some slight changes” proposed during the coming legislation session, he said.

So far, nine corrections officers charged in the initial indictment and the ringleader, Tavon White, have pleaded guilty.

A total of 19 others were charged in the new indictment, including inmates, suppliers and detention center employees. Six are current prison system employees and have been placed on leave without pay.

The indictment describes close relationships between corrections officers and inmates. One guard lived with a former inmate and gang member. Another warned inmates of searches and was heard reciting the gang’s membership oath, a cooperator told the FBI.

Hall, the former member of the disciplinary board, resigned, according to court papers, after pictures of her were found on a cellphone belonging to an inmate, including an apparent “selfie” in her uniform.

The Black Guerrilla Family, which has its roots in California, has in recent years grown to become the state’s largest prison gang, and law enforcement officials say its violence has spilled into the streets of Baltimore. The indictment details two instances in which prison guards allegedly opened jail cells or turned the other way to allow gang members to assault inmates who were not part of the gang.

Many of the defendants were scheduled to make initial appearances in court Thursday afternoon and could face a maximum sentences of 20 years in prison, prosecutors said.

John Wagner contributed to this report.