Police say former NFL star Junior Seau has been found dead in an apparent suicide at his home in Southern California.

Police arrived at Seau's home in Oceanside, Calif., at about 1 p.m. EST after witnesses reported hearing a gunshot inside the house.

SLIDESHOW: Junior Seau: A Career In Pictures

Oceanside Police Chief Frank McCoy said Seau's girlfriend reported finding him unconscious with a gunshot wound to the chest Wednesday. McCoy says lifesaving efforts were unsuccessful.

"This case at this point is being investigated as a suicide. A handgun was found near the body," McCoy said.

Seau's mother, Luisa Mauga Seau, appeared before reporters, weeping uncontrollably.

"I'm shocked, but I appreciate everybody's over here, (showing) your love to my son," she said.

"My brother was a loving brother, a caring citizen, so I would appreciate if you guys would just please honor his last day and give us some kind of peace," Seau's sister said.

Seau played 19 seasons in the NFL, including three with the Dolphins from 2003-2005.

A 12-time Pro Bowler, Seau was considered to be one of the greatest NFL players in league history.

Seau was a standout linebacker with the University of Southern California before going to the San Diego Chargers, whom he led to the Super Bowl following the 1994 season. He remained with the Chargers until 2003 and after his stint with the Dolphins, played for the New England Patriots before retiring after the 2009 season.

In October 2010, Seau survived a 100-foot plunge down a seaside cliff in his SUV, hours after he was arrested for investigation of domestic violence at the Oceanside home he shared with his girlfriend. The woman had told authorities that Seau assaulted her during an argument. 

There was no evidence of drugs or alcohol involved in the crash, and Seau told authorities he fell asleep while driving. He sustained minor injuries.

Seau's former Dolphins teammate, Jason Taylor, released the following statement: "I'm shocked and saddened. Devastated, really. Junior was one of the most positive, uplifting people I have ever known.  He was always full of life and energy and had an infectious spirit that lifted everyone around him. Junior called everyone 'buddy' and treated them like he had known them forever. It would be easy for me to say he was a great friend and teammate, and a tremendous competitor, but that would be selling Junior short. Junior Seau was an individual of great honor and integrity, a leader of men and someone with a deep rooted passion for giving of himself to make the people, the community and especially the children around him better. This is an immeasurable loss for so many. My heart and prayers go out to Junior's family, Gina and their children. I'm going to miss you buddy."

Miami Dolphins CEO Mike Dee released a statement Wednesday afternoon, saying, "We are stunned and saddened at the passing of Junior Seau. During his time with the Dolphins, he made a unique contribution to the team and the South Florida community."

"Junior was one of a kind. The league will never see anyone like him again," the statement continued. Click here to read the entire statement.

Dolphins great Zach Thomas played with Seau in South Florida and spoke about his time alongside him on the field, "As a young linebacker, Junior was my hero growing up and once I had the opportunity meet him I saw that he was everything I hoped he would be and more. Getting the chance to play along side of Junior Seau, the greatest linebacker to ever play the game, made my dreams come true. I am absolutely devastated to hear this news. Today I lost my hero, my friend, my buddy."

The Miami Dolphins also sent out a tweet saying, "The entire Dolphins family sends condolences to the family, friends and former teammates of Junior Seau."

Reggie Bush tweeted, "R.I.P. Jr. Seau one of the greatest players to play the game!"

Terrell Owens wrote, "God Bless Junior Seau & his family! My heart & condolences go out 2 his family. May u RIP!"