College Station police say a gunman killed a Brazos County constable and a bystander and wounded a police officer and another bystander near Texas A&M University just after noon today.

Brian Bachmann, the longtime Brazos County constable, an elected position, was attempting to serve eviction papers at a home in the historical district of College Station about 12:15 p.m. CT (2:15 p.m. ET) when someone inside shot him as he approached.

Police came under fire when they responded, and a 30-minute gunbattle ensued. The gunman was mortally wounded and he died in custody, police said.

The university, about 90 miles northwest of Houston, issued a Code Maroon emergency just before 12:30 p.m. CT, instructing students and school personnel to avoid the area.

Update at 8:52 p.m. ET: The Dallas Morning News has posted the Texas driver's license photo of Thomas Caffall, reportedly the gunman.

The Morning News also reports that College Station officials have corrected the age of the dead bystander, Chris Northcliff, saying he was 43. Earlier statements had said he was 65 and 51.

Update at 8:24 p.m. ET: Citing several sources, The Eagle is identifying the gunman as 35-year-old Thomas Caffall. It says his Facebook page has multiple photos of guns. Police have not released the gunman's name.

Police said that besides the gunman and Bachmann, a former sheriff's deputy, the dead include 51-year-old College Station resident Chris Northcliff, who was walking down the street when the gunman opened fire. Police earlier said a 65-year-old man had been killed.

A 55-year-old woman was also wounded while walking down the street, but her identity has not been released. Police said she underwent surgery and is listed in critical condition.

College Station Police Officer Justin Oehlke underwent surgery for a gunshot wound to the calf. Two other College Station police officers suffered injuries not from gunfire.

Update at 5:38 p.m. ET: The dead civilian is a 65-year-old man, the assistant College Station police chief says, according to the Associated Press.

Update at 5:08 p.m. ET: A memorial page for officers killed in the line of duty says Bachmann had served as the elected constable of Precinct 1 in Brazos County for 13 years and was in law enforcement for 20 years. He is survived by his wife and children.

Before Bachmann, the last Brazos County Precinct 1 constable to be slain was Marcellus Randall "Pet" Millican, who was killed Dec. 14, 1889.

Update at 5:06 p.m. ET: The gunman was shot apparently after a brief chase, The Eagle reports, though police have not officially confirmed that.

Update at 4:40 p.m. ET: At a news conference, Assistant Police Chief Scott McCollum said Constable Bachmann was first to arrive at the house in the 200 block of Fidelity Street. When police officers arrived, they found him down in the front yard, and officers began taking fire, the Houston Chronicle says.

The university says it does not yet know whether the gunman is a student or otherwise associated with the school.

The university is between semesters, so few students are around. The fall term begins Aug. 27, the Chronicle says.

Update at 4:18 p.m. ET: Witnesses tell The Eagle that the gunman, still unidentified, was shot by SWAT officers, but police have not confirmed that.

Update at 4:13 p.m. ET: College Station police report that the wounded officer was shot in the leg and is listed in stable condition. A female civilian is in surgery at St. Joseph Hospital in Bryan. Two other police officers suffered non-life-threatening injuries. Earlier, there were reports of one person experiencing chest pains and another dizziness.

Update at 4:03 p.m. ET: The gunman has died, police say, the Associated Press is reporting.

Update at 4 p.m. ET: The Eagle names the dead officer as Brazos County Constable Brian Bachmann, who was shot while serving paperwork.

The paper also says the gunman has died.

Update at 3:48 p.m. ET: Police say the gunman was shot before being taken into custody.

CNN reports the gunman is the dead civilian, but police have not confirmed that.

Earlier reports indicated the shooting may have resulted during an eviction at a house in the historical district.

Update at 3:43 p.m. ET: Police also say one civilian has died.

Update at 3:36 p.m. ET: The local Eagle newspaper, KBTX and the Associated Press are now reporting that one officer has died.

Update at 3:17 p.m. ET: Two police officers and one civilian were wounded, a Bryan Police spokesman says, the Associated Press reports.

Original post by Douglas Stanglin:

Update at 2:35 p.m. ET: The shooting incident occurred a few blocks off campus, Texas A & M University spokeswoman Sherylon Carroll tells USA TODAY's Donna Leinwand Leger.

Carroll says she learned of the shooting from the campus police chief, who asked her to alert students, faculty and staff to avoid the area. Within 15 minutes, police called to say the shooter was in custody, Carroll says.

"We are OK now," Carroll says. "For a while, it was scary."

Update at 2:33 p.m. ET: The Eagle, the College Station newspaper, reports that the incident appears to have started on Fidelity Street near George Bush Drive, not far from the A&M Former Student's Association building.

Other media reports say the shooter apparently had barricaded himself into a building.

Update at 2:27 p.m. ET: KBTX reports it has confirmed that more than one law enforcement officer had been wounded.

KBTX quotes a spokesperson for the College Station Police Department as saying there were no confirmed fatalities.

"The scene is reportedly under control and there is no longer a danger to the public," KBTX report.

Update at 2:22 p.m. ET: The College Station newspaper, The Eagle, reports that police scanners referred to two officers being wounded, but that was not immediately confirmed. (Correction at 2:56 p.m. ET: We earlier wrongly referred to The Eagle as the school newspaper.)

Update at 2:18 p.m. ET: KHOU.com reports that at least two people were shot. KHOU reports that police say the suspect was firing shots from a house near the campus.

Update at 2:14 p.m. ET: Police officer Seaton, in her interview with CNN, said she did not know at this time the extent of the injuries.

Update at 2:12 p.m. ET: Brazos County police scanners report at least two people "are down."

Update at 2:11 p.m. ET: College Station, Texas, police officer Rhonda Seaton tells CNN that "multiple people" have been injured.

Update at 2:06 p.m. ET: Here is the university's initial report on its website:

Avoid Area. CSPD reports an active shooter in the area immediately southeast of the intersection of Welborn Rd and George Bush Drive. Please avoid the area. Residents in the immediate area need to remain inside their residence.

No further details were immediately available.