PHOENIX - Two 15-year-old girls were killed by a single gunshot each at Glendale's Independence High School, according to police; the weapon was found nearby.

Police said the shooting was a murder-suicide and that a suicide note was found on scene. Officials said that evidence found on scene lead them to believe that one of the girls took the life of the other girl before taking her own life. Detectives also said that the girls were in a relationship.

Police are also not identifying the two victims, but the sister of one of the victims spoke with 12 News and identified her sister as May Kieu, who was killed in the shooting. Officials said the teens were found near the cafeteria under a covered patio on campus.

MORE: Shooting victim's sister speaks out

What we know:

-Two 15-year-old sophomores, both girls, killed just before 8 a.m. near the main building
-Police said the shooting was a murder-suicide and a suicide note was found on scene
-Weapon found near their bodies
-Police responded within two minutes, did not search for a shooter
-Parents were asked to wait at nearby Walmart
-Students were eventually allowed to contact parents
-Crisis Response Network available at 1-800-203-2273 (CARES)

First responders reached the scene within two minutes of the school calling 911, according to police. The resource officer stationed at the school also responded to the scene.

One weapon was recovered near the two bodies, which had one gunshot wound each and were declared dead outside the school's cafeteria area.

Glendale Police Department spokesperson Tracey Breeden said there are no suspects or persons of interest in this case, and they did not have any witnesses come forward yet.

PHOTOS: Independence High School shooting

"We realized it was not an active scene when we got here and then contained once we knew that," Breeden said.

Breeden also said police were not aware of any threats to any individual person at the school before or after the shooting.

Glendale Union High School District posted on its Facebook this morning confirming that no active shooter was on campus and the school was in a lockdown.

While the school was on lockdown, the students were not allowed to use their cell phones. Just before 9 a.m., the school's principal emailed teachers to allow their students to contact their parents via cell phone.

Glendale Unified High School District superintendent Brian Capistran said the cell phone ban during lockdowns is in place to keep rumors from spreading on social media.

"Typically in this situation we don’t use phones," Capistran said. "But we got a flood of calls from parents not getting social media or automated calls so we worked with teachers to get students to contact their parents."

VIDEO: Investigators describe what they discovered on scene

The school asked parents to wait at the Walmart parking lot at 75th and Glendale avenues, where a Mercy Maricopa crisis mobile team was on-scene.

Officials also urged concerned parents and those worried about the situation to contact the Crisis Response Network at 1-800-203-2273 (CARES). That hotline is still available.

Buses picked up parents from the parking lot and took them to the school to meet and pick up their children, but parents were visibly anxious, many waiting to meet their children for more than an hour

WATCH: Parents describe frustration while waiting to pick up their children.

Glendale Mayor Jerry Weiers said his daughter attended IHS and he has faith in the safety of the school.

"We are very very sad to see this tragedy," he said, "but I do feel that IHS is one of the safest high schools and they’ve done great things to prepare for something like this.

Police shut down 75th Avenue from Glendale Avenue to Bethany Home Road, reopening the road around 2:30 p.m.

SOCIAL: People on social media share their thoughts on the shooting

According to the school's website, about 2,000 students are enrolled at IHS.

Capistran said IHS students should expect to attend school Tuesday after Monday's planned day off for Presidents' Day.