The U.S. Postal Service, which is charged with screening mail for safety, failed to detect bullets that were sent with threatening letters to at least two Baltimore judges in the past week.
And it's unclear if it could. There appears to be no technology in place to identify the ammunition sent in the mail.
The oversight raises questions about mail security and who is responsible for ensuring recipients' safety in the wake of five suspicious mailings, some with a powdery substance inside, that were delivered to City Hall and Baltimore Circuit Court on Friday and Monday. The courts say it's not their job to screen packages, and the postal system says it can do only so much.
A joint investigation into the letters, sent to four judges and City Hall, has been launched by Baltimore police and the U.S. Postal Inspection Service.
"Even though the powder contained in the mailings is not harmful, the threatening mailings not only constitute a federal crime, but they caused alarm to victims and institutions," said U.S. Postal Inspector JerVay Rodgers, who works in the Washington division. She said postal inspectors will aggressively investigate "anyone who mails these types of threats, real or hoax."
But there's little that can be done if a package isn't initially identified as suspicious, she acknowledged.
The Postal Service screening system consists mainly of employee judgment. They ask a series of familiar questions at the service counter for mailings weighing 13 ounces or more - anything hazardous, breakable or perishable? - and expect truthful answers. And they report suspicious packages for inspection or run them through a biohazard detection system.
The system was set up in more than 270 processing and distribution centers, including Baltimore's, after the 2001 anthrax attacks, in which letters containing the deadly spores killed five people and sickened 17 others.
But so far, the system - used more than 8 million times nationwide since 2003 - has never alerted authorities to a single piece of suspect mail, Rodgers said.
Rodgers also said that the postal system is not responsible for courthouse safety through special screening. "That's on their side of the house."
Judiciary spokeswoman Angelita Plemmer declined to provide details on the courts' security procedures.
"The court is not responsible for screening the mail," she said, directing security questions to the Postal Service. "We are certainly aware of the public safety issues, and we're certainly doing everything in our power to ensure the protection of the public and our employees."
On Friday, Circuit Judge Wanda K. Heard sent an e-mail to dozens of colleagues, later obtained by The Baltimore Sun, saying her law clerk had opened a priority-mail envelope "sent to me with a bullet inside and a threatening note." She added that the mayor had received a similar note.
"It should have never reached my law clerk or any member of my staff, for that matter!!! There is a breakdown in the system. The mail should have been scanned. Obviously, it wasn't," Heard wrote. "Anything could have been inside!! Anything!"
Minutes later, Administrative Judge Marcella Holland replied that the incident had already been reported.
"The USPS is investigating because its employees did not follow procedure. We will await their report and response," Holland wrote.
On Monday, she too received a threatening letter, as did two other judges and someone at City Hall. Rodgers denied that it was as a result of postal employees not following procedures, however.
Police will not say to whom the City Hall letter was addressed, and city officials declined to comment. Officials evacuated the building for more than 40 minutes Monday after a clerk discovered a letter with white powder inside.
Circuit Judge M. Brooke Murdock also received a letter Monday containing a bullet and white powder, she said. Police sent a hazardous-materials team to investigate, but the courthouse wasn't evacuated.
Prosecutors grumbled among themselves Tuesday about the disparity in the way the matters were handled at the courthouse and City Hall.
"There is some degree of surprise at the difference," said Margaret T. Burns, spokeswoman for the state's attorney's office. She said her office, housed within the courthouse, was not evacuated or told of a security threat.
"The only way we knew that this was going on was as a result of reading it in the media," Burns said.
Plemmer, the judiciary spokeswoman, said the courts notified law enforcement officials as soon as the letters were received, and followed their protocols, which didn't call for evacuation. The judiciary also warned leaders of the state's circuit and district courts, as well as the chief judge of the Court of Appeals of Maryland.
Baltimore Sun reporter Julie Scharper contributed to this article.