Hank Hunt's granddaughter tried calling 911 from the East Texas hotel room where she could hear her mother dying, just as she was taught to do in an emergency. She didn't know she had to dial 9 on the hotel phone first.

"Papa," Hunt remembers the 9-year-old telling him later. "I tried, but it wouldn't work."

Now Hunt has launched a national push to require hotels and other businesses to do away with dialing anything before calling 911. So far, an online petition for a federal law has gotten 390,000 signatures, and one 911 advocacy group says Hunt has hit on a perhaps under-documented issue.

"I never dreamed that it would take a life of its own like this," Hunt said this week. "There's been a lot of good people out there helping us."

Hunt's petition calls for "Kari's Law," in honor of his daughter, Kari Hunt Dunn, who was stabbed to death inside a Baymont Inn hotel, allegedly by her estranged husband. The law as described by the petition would require hotels and motels to upgrade to "Enhanced 911" systems that would let guests call for help just by dialing 911 and give the operator the caller's exact location.

The National Emergency Number Association, a group representing 911 call takers and industry professionals, says such changes are long overdue. Government affairs director Trey Forgety said the association did not know exactly how many callers try to dial 911 and fail. But officials hear "with some regularity" from member law enforcement agencies about callers who couldn't get through, he said.

"If it makes it onto our radar a few times a year, then it does sort of beg the question: How many identical situations are out there that we just don't hear about?" Forgety said.

Police in Marshall, about 150 miles east of Dallas, say Brad Dunn entered a room in the Baymont Inn where Kari Dunn and their three children were staying. Hunt said Brad Dunn took his estranged wife into the bathroom, leaving the children outside.

Det. Sonya Johnson said that as Brad Dunn began stabbing Kari Dunn, their eldest daughter tried to call for help. Four times, Hunt said, she dialed 911. Each time, it came up with static. Hunt said the children eventually ran into the hallway and found someone in a nearby room to call 911.

Brad Dunn would flee with their younger daughter and was arrested in a neighboring county. He's now accused of murder and being held on $5 million bond. His attorney, Scott Rectenwald, declined to comment.

Hunt and Johnson could not say how much extra time it took to call 911 due to the delay, or whether that time could have saved Kari's life.

"We have no sense of knowing, because she never did make the call," Johnson said.

There were no immediate figures available on how many hotels require guests to dial 9 to make outside calls. Wyndham Hotel Group, which owns the Baymont Inn brand, said in a statement it was "looking into the issues that have been raised in the petition," but declined to say how many of its hotels require guests to dial 9 or what changes it was making.

Hotel experts say an industry-wide change could be made without a national law.

Don O'Neal, a Dallas-based hotel technology consultant for more than 30 years, said one hotel he worked with recently made 8 the code for outside calls -- but programmed 911 calls to work without a prefix.

A handful of hotels either use old systems or more basic phone systems that aren't intended for hospitality use.

"If this particular hotel did not have it set up properly, it was strictly because they didn't have the programming done, or else they had a telephone system that was not very current," O'Neal said.

One issue is that a direct-dial system might notify police, but not a hotel's front desk, about an urgent situation to which staff could respond more quickly, said Chad Callahan, safety and security consultant for the American Hotel & Lodging Association. Callahan said he didn't think a law was necessary.

"Working together on these things, hotels can be reasonable about it," Callahan said. "As long as they understand it, they'll probably do the right thing in most cases."

But NENA officials said some requirements are needed for all businesses that serve guests.

"The brand knowledge of 911 is one of the highest in the world," said Ty Wooten, the group's education director. "When you put anything or do anything that requires someone to do something other than dialing 911, it lends itself to potential problems."