[Updated at 6:08 p.m. ET] "We don’t know exactly if she had a heart attack or a stroke,” Harris County sheriff's spokeswoman Christina Garza says of the female who was hospitalized with an unspecified medical condition.
[Updated at 5:44 p.m. ET] According to officials at a news conference, four people were taken to hospitals – three who were injured and one who suffered an unspecified medical condition – but the account of who they were differs from information we received earlier.
One person – a school maintenance worker – was accidentally shot during an altercation between two other people, Harris County sheriff's Maj. Armando Tello said. That man was shot in the leg, is in his mid-50s, and is in stable condition, said Richard Carpenter, chancellor for the Lone Star College system.
The two "persons of interest" suspected of fighting each other also were injured, Tello said. Tello did not say how they were injured.
Tello also said one handgun was involved in the incident. When asked whether only one person was armed, Tello said he didn't know. Earlier, a school spokesman had said two gunmen were involved in the incident.
Also, a fourth person – a female who has a student ID – was taken to a hospital with some sort of medical condition, Tello said. Earlier, a federal law enforcement source told CNN that someone had suffered a heart attack.
Carpenter said the fight happened in a courtyard area between two buildings. That seems to mesh with what a law enforcement source said earlier about the incident happening in an outside area between a library and a cafeteria.
[Updated at 4:52 p.m. ET] A law enforcement official briefed on the investigation says the shooting appears to have taken place in an outside area between a library and a cafeteria, CNN's Carol Cratty reports.
[Updated at 4:30 p.m. ET] Two suspects are now in custody, CNN affiliates KHOU and KTRK reported. CNN has not yet independently confirmed this information.
Authorities are expected to conduct a news conference at about 5 p.m. ET.
[Updated at 4:03 p.m. ET] Police believe the second suspect fled into woods nearby, a law enforcement source briefed by officers on the scene told CNN.
Authorities are focusing their search on the wooded area, which is adjacent to George Bush Intercontinental Airport, the source said.
[Updated at 3:59 p.m. ET] An unidentified Lone Star College student who says she witnessed some of the shooting told CNN affiliate KHOU that an argument between two people preceded the gunfire.
A gunman, she said, told someone: "I don't want to fight you; I'm not trying to go to jail."
The witness appeared to reference only one gunman; it wasn't clear whether she saw a second gunman. She said he "actually turned away from the situation" at first but eventually pulled a gun out of a backpack. She said she heard about nine shots.
"I think it was a bunch of crap that could've been resolved and never should have gone that far," the witness said.
[Updated at 3:23 p.m. ET] Texas Gov. Rick Perry is being briefed about the situation by law enforcement personnel, Perry spokesman Josh Havens said.
"(Perry's) thoughts and prayers are with those that have been impacted," Havens said. "We have nothing more to add at this point, but the governor will continue to closely monitor the situation."
[Updated at 3:17 p.m. ET] A freshman who was in a nearby classroom, Amanda Vasquez, tells CNN's Brooke Baldwin that she heard about six shots. She says she heard from other people that some shooting happened in a library, but she believes that the gunshots she heard came not from the library, but from the hallway outside her class.
"I was in the academic building, waiting for English class to start. I heard about six shots, and kids started rushing down the hallway. A few came into our class. It really happened so fast," she said.
She said people were shouting, and she hid under a table in a corner of the classroom. She called her mother.
"I called my mom to (let her know) I was OK (and that) I loved her, just in case anything was going to happen," Vasquez said. "... At first she didn’t believe me ... but I kept telling her it's happening and need you to call the cops."
[Updated at 3:06 p.m. ET] Someone – a fourth person – suffered a heart attack, according to a federal law enforcement source who is receiving reports from the scene, CNN's Carol Cratty reports.
So, recapping what we've been told:
– Three people, including a gunman, were wounded in a shooting between two people on the North Harris campus of Lone Star College in Houston, school spokesman Jed Young said.
– The second gunman is on the loose but not believed to be on campus, Young said.
– A fourth person suffered a heart attack, according to the federal law enforcement source.
– The shooting happened at a campus library, the federal law enforcement source says.
– No deaths have been reported.
[Updated at 2:54 p.m. ET] Two wounded people have been taken to surgery at Ben Taub Hospital and are in "relatively serious condition," CNN affiliate KTRK reported. They were conscious when they arrived at the hospital, KTRK reported.
[Updated at 2:43 p.m. ET] Three people – one suspected shooter and two people caught in a "crossfire" – were wounded in a shooting that appears to have been between two people at the Lone Star College campus in Houston, school spokesman Jed Young said.
The wounded suspect is in custody, and the second gunman is on the loose but not believed to be on campus, Young said.
Authorities believe the school is "under control, but the school is still being evacuated," Young said.
Young said he doesn't know the conditions of the wounded. He said the shooting – apparently between two gunmen – was reported at about 12:31 p.m. CT.
Two apparently unintended targets were shot in a "crossfire," he said.
[Updated at 2:28 p.m. ET] The FBI and ATF have sent agents to assist local authorities, according to Shauna Dunlop with FBI Houston and Franceska Perot with ATF Houston.
[Updated at 2:27 p.m. ET] A witness told CNN affiliate KPRC that she hid underneath her desk while she heard five or six gunshots at Lone Star College.
[Updated at 2:26 p.m. ET] One person has been transported to Houston Northwest Medical Center, according to spokeswoman Ashley Walton.
She would not give any further details about the patient.
[Updated at 2:14 p.m. ET] Students were filing out of what CNN affiliate KHOU reports is the library on campus.
[Updated at 2:10 p.m. ET] Video from CNN affiliate KPRC shows law enforcement personnel herding people from one part of the campus to another.
[Updated at 2:02 p.m. ET] Students at a Lone Star College campus in Houston have been asked to take shelter after reports of a gunman on campus, a school spokesman said.
More than 10,000 students are at the North Harris campus of Lone Star College, spokesman Jed Young said.
Footage from KPRC showed a large number of law enforcement personnel on campus, and at least two people being wheeled on gurneys toward ambulances.
This story is developing. We'll post more details as we get them.