Anne Arundel County detectives investigating the fatal shooting of a Baltimore man in a neighborhood near Arundel Mills mall last month had two solid leads: In the minutes before his death, according to charging documents, Derrin Davon Thomas had been in contact with someone identified in his cell phone as Dip, and records showed Dip's phone had connected with nearby cell towers at the time of the killing.
The next step was to figure out who Dip was.
Detectives, tipped off that the shooter might have been from Prince George's County, turned to officers there, who searched a database of nicknames and other identifying features of known criminals and their associates.
Dip, it turns out, is more formally known as Marvin Little, 20. Police say he drove a car that matched a witness' description of the getaway vehicle, and his fingerprints were found on a box inside the victim's truck. Little was arrested Jan. 18 in Temple Hills and charged with first-degree murder.
Years ago, such information might have been kept on index cards, painstakingly searched by hand. But a criminal's true vital statistics - aliases, nicknames and distinctive marks or tattoos - are easier to search these days as departments across the country upload information buried in case files or discussed in precinct chatter into computer databases.
"In today's world, everybody thinks DNA is huge, but these are the old-fashioned traditional police techniques that are tried and true," said Andrew Karmen, a criminologist at John Jay College of Criminal Justice in New York. "It allows you to cut to the chase and reach into a pile of a thousand suspects and end up with a handful, or sometimes just one."
Police departments around the country rely on these databases, and they are becoming faster and more powerful. In New York City, police use a sophisticated computer network that acts like an Internet search engine to relay information to officers in the field. Among the data gathered are the names of people who have visited a convict in prison and recordings of 911 calls made from any address in the city over the past 10 years.
Doug Ward, a retired Maryland State Police major and director of the Division of Public Safety Leadership at the Johns Hopkins University, said technological advances and new crime-fighting concepts - which include combating the growing presence of gangs - are helping agencies inch closer to more widespread sharing of intelligence.
Last month, Gov. Martin O'Malley and Rep. C.A. Dutch Ruppersberger announced a $2.8 million initiative that would link crime databases about gang members along the East Coast. The databases include nicknames, addresses, associates, even tattoos.
With criminal history and addresses already available to most agencies through state and federal databases, the advantages of such a network lie in the ability to share more nuanced information.
"If you don't have a database that can search multiple records, you'll never tie [the information] together," Ward said. "That becomes really important in regional crime analysis as well - if each jurisdiction only looks at their own data, they're not connecting the dots."
Tattoos can be crucial when exploring the inner workings of a gang - an "M.O.B." tattoo, signifying "Member of Bloods," might be enough for authorities to link someone to the Bloods.
Baltimore police spokesman Troy Harris said officers in the city have long relied on a computer program that includes information about the suspect, including height, weight, complexion and previous addresses. As detectives learn more about a person, "they'll add in nicknames and tattoos, that type of information, so they can cross-reference," Harris said. Prince George's County police described a similar system.
The databases can also weed out suspects, said Cpl. Michael Hill of the Baltimore County Police Department. "Even though some people share locations of tattoos or nicknames, once the detective is able to identify people with that information he's able to look closer at other descriptions," he said.
Through a spokeswoman, Anne Arundel County police refused to discuss their system of tracking nicknames or other identifiers except to say that the department "is always looking to the future to utilize technological advances to make our system better."
Thomas' killing provided a geographic challenge for Anne Arundel homicide detectives. The victim was from West Baltimore. The eventual suspect was from Prince George's County. And the killing took place about halfway between, in Hanover, just off Interstate 295 in Anne Arundel County.
According to charging documents, detectives gathered evidence and took witness statements at the scene. They reached out to Baltimore police, where an officer with an informant said that the shooter had been driving a silver-colored BMW and was believed to be from Washington or Prince George's County.
Detectives then turned to Prince George's County, which ran the nickname Dip and came up with one match: Little. A Prince George's detective also said that he had recently seen Little in a silver-colored BMW. The fingerprint match led investigators to get an arrest warrant, police said.
Officers from Anne Arundel and Prince George's counties, along with the U.S. Marshals Service, found Little about 6:30 a.m. Jan. 18 in Temple Hills and saw him getting into the the car. Authorities, who activated their lights and sirens and blocked the vehicle, said Little backed up and struck a marshal's vehicle in an attempt to flee. Officers subdued Little with a Taser gun, according to charging documents. He is being held at a county jail. He has pleaded not guilty to the murder charge.
Karmen, the criminologist, said that even the most obscure information can help crack a case.
"Sometimes, something as simple as saying, 'You got any nicknames?' solves a murder."