On Monday, a lawyer filed a court motion that, if approved, could undermine the cellphone data used by prosecutors to convict Adnan Syed, the subject of of last year’s Serial podcast, over 15 years ago.

The motion focuses on the fact that, according to Syed’s attorney C. Justin Brown, the Baltimore police ignored the cell phone data’s cover sheet, which clearly stated that incoming call data is not reliable for pinning down the call’s location. And the cellphone data used in Syed’s case was, of course, from an incoming call.

From the appeal:

It is now known, however, that when AT&T provided the cellular tower data to the State, AT&T explicitly warned the State that: “Outgoing cals only are reliable for location status. Any incoming calls will NOT be considered reliable information for location.”... Despite this unambiguous warning, the State presented at trial evidence of incoming calls to determine location and used this to convict Syed. The State then relied on this supposed proof in arguments to the Post-Conviction Court.

The incoming call data was used by prosecutors to argue that Syed was clearly in the Leakin Park area the night police believe murder victim (and Syed’s ex-girlfriend) Hae Min Lee’s body was buried. According to The Baltimore Sun, “the fax cover sheet from AT&T was included in [original defense lawyer Cristina] Gutierrez’s file.” But the attorney simply “failed to act on it.” Just another misstep in a long line of ineffective counsel by Gutierrez, who died in 2004.

The calls originally corroborated Jay Wilds story, who confessed to allegedly helping Syed bury Lee’s body at Leakin park. But if that call data is successfully thrown out, it would mean that Asia McClain, who might provide an alibi for Syed at the reopened hearings, could offer a successful counter argument.

As Brown wrote in the motion, ““If AT&T, the architect and operator of the cell tower network, did not think incoming calls were ‘reliable information for location,’ it is unfathomable that a Baltimore City Circuit Court judge would have allowed an expert opinion ... under this method.”

Syed, who was convicted in 2000 of Lee’s murder, is serving a life sentence.

Contact the author at ashley@gawker.com.