In the wake of a high-profile killing when a responding officer was dispatched to the wrong address, Charlotte-Mecklenburg police have tightened their dispatching policy, even as they say it's probably impossible to eliminate human error from the 911 system.

The change, requiring 911 call-takers to confirm addresses, comes against a national backdrop in which experts say there's no universally accepted standard for how to verify all addresses during emergency calls.

The department's 911 system came under fire after Danielle Watson's body was found behind a south Charlotte Dumpster on Jan. 14 - about six hours after her boyfriend, Keith Smith, called police saying he thought a robbery was happening at the Flying Biscuit Café in Ballantyne, where she worked as a manager.

In CMPD's 911 system, call-takers answer 911 calls and relay the information to dispatchers, who then talk with police officers over the radio.

For reasons that remain unclear, the call-taker typed in the wrong address. He is on administrative leave. The responding officer, who has worked in the department's South Division since 2000, searched a business park near the erroneous address, but not the Flying Biscuit, located about four miles away in the StoneCrest shopping center.

The officer has not been disciplined.

Mark Anthony Cox, a 22-year-old who was released from prison in November after serving time for robbing a Sonic restaurant where he worked, was charged with murder. Since Smith was pregnant, prosecutors say they will also seek to charge Cox with the murder of her unborn child.

Charlotte-Mecklenburg police use a sophisticated computer system to help respond to 911 calls. But at its core, the dispatching system is based on how well people communicate, said Capt. Mike Campagna, who oversees the department's communications division.

About 120 call-takers and dispatchers handled 800,000 emergency calls last year, down from 919,000 in 2007. (He couldn't offer a definitive explanation for the drop in volume).

"It is a human process," Campagna said. "It is two people talking to each other and trying to communicate information. We don't want an automated system that says, 'Please listen to all the menu options because they have recently been changed. Press 'one' for robbery. Press 'two' for burglary.' "

The call-takers, Campagna said, "really have to be astute listeners to catch not just what the person is saying but what they're not saying."

911 call goes awry

In Watson's case, Smith dialed 911 at 12:05 a.m. and told a call-taker police were needed at 7930 Rea Road, which is the address of the Flying Biscuit Café. He didn't clearly articulate the numbers, however, and some listeners, including Campagna, have said it sounds like 3930 Rea Road - the address to which the police officer later responded.

Smith gave the name of the business as "Flying Biscuits," and told the call-taker he believed it was being robbed because his girlfriend called him and abruptly hung up. He could hear yelling in the background.

The call-taker didn't confirm the address of the business or its name. It's unclear which details - besides the incorrect address and name of the business - were conveyed to the dispatcher and, ultimately, the officer.

The police officer went to 3930 Rea Road, a legitimate address. But for reasons that remain unclear, she thought she was looking for a business called "Plum Biscuits." Police have declined to offer a detailed explanation of her actions.

Campagna said the failure to confirm the address went against the training given call-takers and dispatchers. They were encouraged to confirm previously; the new policy change makes confirmation mandatory.

Most calls are prioritized using a 3-point scale, with one being the highest priority, and requiring an officer to be dispatched within three minutes.

(The full scale covers nine priority levels, with Priority 9 often used for animal-control calls.)

The call-taker is also expected to characterize the nature and seriousness of the emergency, which affects how quickly an officer will respond.

Smith's call was entered as a "check the welfare" call, and was set as a Priority 3. Officers have 15 minutes to respond to Priority 3 calls; the officer arrived at 3930 Rea Road 12 minutes after being dispatched.

Police have not said whether they believe the call was categorized incorrectly. Typically, the highest-priority calls involve an immediate threat of injury or death. Police also tend to give higher priority to calls where there's a chance of catching a criminal in the act.

Campagna said a 911 call where there's no indication of an imminent threat would probably not be a Priority 1. Asked if the fact that Smith said he "believed" the restaurant was being robbed might have led the call-taker to assign a lower priority, Campagna declined to comment directly on his conversations with the call-taker.

The call-taker did not return messages seeking comment.

"There are a lot of things going on," Campagna said. "Something must have factored into making him believe the situation wasn't as imminent."

Police didn't arrive at the Flying Biscuit until the next morning, when employees arriving for work found the safe open and money missing. Watson's body was found behind a nearby Dumpster.

Smith, who had left his number with the call-taker, says he went to sleep after calling police. He had been promised a callback when police found out what was happening with his fiancée, but he says he never received one. Typically, the officer or dispatcher calls back when there's a problem finding the scene of the emergency.

Police officials said in an email that the officer "indicated in her notes that she attempted to make a return call, but was unsuccessful."

Modern tech, human error

Dispatchers across the United States haven't come to a consensus about what works best. There aren't any national standards for dispatching, says Crystal McDuffie, communications center and 911 services manager for the Association of Public-Safety Communications Officials.

McDuffie said practices vary by state and city, depending on factors ranging from regional dialects to the experience level of dispatchers to the amount of technology a department has.

She said dispatching organizations have even struggled with reaching a consensus on how to verify addresses, which was the main issue in Watson's case.

"Some will say repeat it back. Some will say have the caller repeat it again. Some will say verification will be looking at the screen," McDuffie said. "I think at best you would get a national standard that says 'verify.' "

McDuffie listened to the 911 tape of the Flying Biscuit call. She said she didn't hear anything egregious done by the call-taker - his performance will ultimately be based on the standards of Charlotte-Mecklenburg police.

Campagna said he's using this incident to reinforce to his dispatchers the need to be diligent in even the most routine calls.

"You never know which call is the call," Campagna said. "You never know what's on the other end of that phone line. You have to deal with every call with the highest level of attention to detail."

Staff writer Meghan Cooke and Staff Researcher Maria David contributed