Some people received duplicate alerts on their mobile phones, some not until hours after the incident, and some as far away as Manitoba.

But despite those glitches, the Amber Alert sent out Thursday to locate a missing 11-year-old Brampton, Ont., girl shows the mobile emergency system seems to be doing what it was intended to do, experts say.

Ontario Provincial Police issued the Amber Alert around 11 p.m. ET, searching for 41-year-old Roopesh Rajkumar and his daughter Riya. A motorist spotted the car described in the alert, and police were able to locate and arrest the man. The girl's body was found about an hour later in his apartment.

Rajkumar was charged Friday with first-degree murder.

"This is exactly why it was designed, and someone who was somewhere at the right time, even at 11:00 [at night], was able to contribute," said security expert Matthew Overton. "Unfortunately, the little girl was already dead."

Overton said he has received several alerts since the CRTC made it mandatory last year for telecom companies to support Amber Alerts on their mobile phone networks.

"It certainly caught my attention, so it has done everything it wants to," he said. "I think from that perspective it seems to be moderated pretty well. I'm not seeing a series of alerts [that] I'm wondering: 'Why should I get that?'"

Roopesh Rajkumar, 41, was arrested on a highway about 130 kilometres north of Brampton, Ont., after an Amber Alert was issued late Thursday. His daughter, Riya, was found dead in his basement apartment shortly before his arrest. (Facebook)

Peel Regional Police said they received a series of emails and calls from people complaining about receiving the late-night alerts that were accompanied by a siren-like sound.

"I appreciate that a lot of people were sleeping, but the immediate need to locate the child outweighed the momentary inconvenience that some people encountered," Const. Akhil Mooken said on Twitter. "Tragically this incident did not have the outcome we were all hoping for but the suspect was located as a direct result of a citizen receiving the alert and calling 911. The system works."

the child outweighed the momentary inconvenience that some people encountered. Tragically this incident did not have the outcome we were all hoping for but the suspect was located as a direct result of a citizen receiving the alert and calling 9-1-1. The system works. 2/2 —@OfficerMooken

That doesn't mean there weren't technical glitches. In a statement, Pelmorex, the company that operates the alert system, acknowledged it received reports that some users received duplicate alerts, as well as some users outside the province, in neighbouring Manitoba, who received alerts.

Martin Belanger, Pelmorex's director of public alerting, said in a statement that the company was reviewing those reports, but that initial checks indicated that devices set with a reminder feature on may cause the alert to repeat until it is acknowledged by the user.

The system also sends simultaneous alerts to multiple distributors. One of the simultaneous alerts remained "active" and resulted in some users receiving the message after the alert had been cancelled, he said.

'Still some problems'

Overton said glitches like those will "carry on a for a while" and "obviously there's still some problems."

"But I think it's going pretty well right now," he said.

Since April 2018, the CRTC has required that all wireless service providers participate in the National Public Alerting System (NPAS) and distribute wireless public emergency messages warning of imminent safety threats such as tornadoes, floods, Amber Alerts or terrorist threats.

Telecom companies wanted an opt-out option or the ability to disable the alarm for some types of alerts, but that was rejected by the broadcasting and telecommunications regulator.

Peel Regional Police Const. Danny Marttini responds to complaints prompted by a late-night Amber Alert. 0:27

The U.S. system classifies alerts at different levels, allowing people to opt out of receiving the less serious ones, according to Sunil Johal, policy director at the Mowat Centre at the University of Toronto. Canada only pushes out alerts at one level — urgent — a policy officials may want to reconsider, he said.

Johal suggested Canada could geotarget the alerts more effectively so that if, for example, something is happening in Toronto, people in Ottawa or Thunder Bay won't necessarily get that same alert.

Tweak the sounds

He said the goal should be finding that "perfect balance where we're warning people but not inundating them with things they can't do anything about."

Overton said it may be possible to tweak the sounds of the alerts yet still allow them to catch the attention of people.

Still, the unnerving sound that frightened and annoyed some people — that, too, means the system is working.

"Because, in a little way, it's supposed to be annoying to catch your attention to something around you that you may not be aware of."