After an off-duty detective was assaulted by dirt bike riders following a street accident in West Baltimore in June, police were hot on the trail of one of the bikes thought to be involved.

The statement of probable cause for the arrest of the man found riding the bike — 22-year-old Kevin Kemp — describes the officers spotting him, his fleeing, the department's Foxtrot helicopter providing support and a "lengthy foot pursuit."

Kemp was charged with a series of crimes and traffic violations, including theft of the bike and failing to stop in an attempt to elude a uniformed officer, but not the assault.

What the court document doesn't mention is that the officers located the bike using information from analysts reviewing footage from a surveillance plane that had been recording huge swaths of the city when the assault occurred.

Instead, the document just says the bike's location "was discovered" as part of an investigation.

In another case in February, in which a pair of elderly siblings were shot, the statement of probable cause for the arrest of 36-year-old Carl Cooper mentions the ground surveillance footage that allegedly shows Cooper firing the shots but makes no mention of the footage from the plane that helped police track him down.

Baltimore Deputy Public Defender Natalie Finegar said the failure by police and prosecutors to disclose such information in the court documents is a major problem.

Police officers routinely include information about video footage from the city's street-level CitiWatch cameras in such statements, Finegar said, and such information always should be disclosed to defense attorneys by prosecutors so that both sides can consider its value.

Simply writing that information was "discovered," without explaining that it came from video evidence, is exactly the "kind of language they used in stingray cases," Finegar said.

The secrecy of the surveillance program added to the anger among city leaders, acoording to reporter Doug Donovan. (Emma Patti Harris/Baltimore Sun video) The secrecy of the surveillance program added to the anger among city leaders, acoording to reporter Doug Donovan. (Emma Patti Harris/Baltimore Sun video) SEE MORE VIDEOS

Baltimore previously became a focal point for the growing national debate over the use of so-called stingray technology, which mimics a cellphone tower and helps pinpoint a device's location by triggering all phones in an area to connect to it. Police typically used the device after obtaining court orders that did not explicitly describe the technology, because authorities agreed not to disclose its use. Prosecutors agreed to drop cases when there was a risk the technology would be revealed.

Such nondisclosure agreements were in place around the country, but the Baltimore pact was one of the first to be revealed. Baltimore police later disclosed that they had used the stingray device thousands of times.

The Maryland Court of Special Appeals ruled that "people have an objectively reasonable expectation of privacy in real-time cell phone location information," and that using the stingray without a search warrant was a violation of the Fourth Amendment.

Finegar's office — which represented Kemp — denounced the secrecy around the stingray program and now finds itself in a similar situation with the aerial surveillance program, she said. It's now demanding to know every case in which such footage was used in order to check if clients' rights were violated — or if video footage exists that might exonerate them.

Kemp was found guilty of a single traffic violation of eluding police and given a one-year suspended sentence and 18 months of probation. All other charges were dropped. He could not be reached for comment.

Cooper's attorney, Margaret Mead, also called the Police Department's undisclosed use of surveillance footage a problem, and it's something she is looking into.

Ross McNutt, the owner of Persistent Surveillance Systems — the Ohio-based company that has spent 300 hours since January recording the city for police — said his analysts have provided "investigative briefs" in 102 cases, but it's not clear how many of those resulted in arrests.

The Baltimore state's attorney's office has said it is reviewing such evidence in five open cases, but has not identified those cases or responded to questions about how many closed cases such evidence was used in.

T.J. Smith, a police spokesman, said he didn't know how many times the footage has been used. He said police don't include all of their evidence against suspects in statements of probable cause, and noted that police work with prosecutors to review evidence and determine charges.

Baltimore Sun reporter Justin Fenton contributed to this article.

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