David Temple had been a star football player at Katy High School in Katy, Texas, and went on to play football at Stephen F. Austin University in Nacogdoches, Texas, where he met Belinda.

Belinda was an accomplished athlete in her own right and taught aerobics during college. After graduation she moved from her childhood home in Nacogdoches to Katy, Texas, to be with David.

David and Belinda were college sweethearts and married in 1992. He proposed to her on the 50-yard line of their college football field at Stephen F. Austin University.

David and Belinda Temple with their son, Evan. By all accounts both were devoted parents.

Both Belinda and David were high school teachers. Belinda was a special education teacher at Katy High School and David was a football coach at Hastings High School, near Katy. When she was murdered, Belinda was eight months pregnant and their son, Evan, was 3 years old.

When David came home on Jan. 11, 1999, he says he saw the back door glass was broken. He says he took Evan across the street to a neighbor’s house, and ran back to check on Belinda. Police say the pattern of broken glass behind this door is a clue.

The back door is open in this photo and you can see the broken glass is off to the left of the door. Detectives thought the glass being off to the side meant the door was open when the glass was broken. The defense says the broken glass could have fallen out in this area as David Temple pushed the door open to rush upstairs and check on his wife.

The other clue that police found suspicious was the TV in the Temple home, which is still plugged in and on the floor on its side. Police thought this did not seem like something a burglar would do.

Police say they also found it suspicious that there was jewelry in plain view in the Temple’s bedroom that was not stolen.

Belinda Temple was found in the bedroom closet. She had been killed by a single shot to the head. The ammunition found with her body was consistent with a 12-gauge shotgun from a reloaded 00 buckshot shell. The medical examiner said Belinda and her unborn baby, Erin, were killed instantly.

The day after Belinda Temple’s murder, police learned that David Temple was involved with a teacher at the school where he taught and coached football: a woman named Heather Scott. Could that have been a motive for murder?

Law enforcement searched for years after Belinda’s murder and never found a shotgun that connected back to David Temple.

Prosecutor Kelly Siegler says she thinks David Temple got rid of the murder weapon somewhere in the rice fields of Katy, Texas.

Riley Joe Sanders III was a student in Belinda Temple’s high school and lived next door to the Temples. Weeks before her murder, Belinda told his parents about his excessive truancy. But Sanders insisted he bore Belinda no ill will and had no involvement in her murder.

David Temple was arrested in November 2004, just weeks after Scott Peterson was convicted of murdering his pregnant wife, Laci, in California -- a case that attracted national media attention.

David Temple’s murder trial began in the fall of 2007. He was represented by famed Texas defense attorney, Dick DeGuerin. The prosecutor, Kelly Siegler, was equally famous for her long string of courtroom successes. Siegler and DeGuerin had a long-standing courtroom rivalry. 

Belinda Temple’s old neighbor, Riley Joe Sanders III, now a grown man, was called to testify for the prosecution. He repeated his assertion that he had nothing to do with Belinda’s murder.

Defense attorney Dick DeGuerin holds a 12-gauge shotgun that was recovered with a spent 00 buckshot shell in it -- the same type of weapon and ammunition used in Belinda’s murder. The gun belonged to Riley Joe Sanders III’s father -- and was being hidden by one of Sanders III’s friends when police found it. 

Police say there was no evidence this gun was used in the crime, but in an interview with police, the friend said he may have cleaned the gun.

Heather Scott married David Temple less than two years after Belinda’s murder. Temple’s lawyer, Dick DeGuerin, admitted the affair did not look good for Temple, but reminded jurors that “being unfaithful doesn’t make you a murderer.”

David Temple was convicted in November 2007 after a four-week trial. His attorney played his 911 call from the day of the murder in closing arguments. The jury convicted him anyway.

Stephen Clappart was an investigator for the Harris County District Attorney’s Office in 2012, when a new tip came in on the case. As Clappart began to investigate and read into the case, he began to have doubts about whether David Temple had killed his wife.

Among the evidence Stephen Clappart found in the old police files were photos of a break-in that happened nine days before Belinda’s murder. Just like in the Temple home, there was glass in the back of the house that was broken to gain entry. Some of Riley Joe Sanders III’s friends later admitted to this burglary. Sanders was not with them.

Clappart turned over his findings to Temple’s new attorneys, Stanley Schneider and Casie Gotro. They got to read the complete 1,319 page police report -- which Temple’s trial attorney did not have access too. They say many items of evidence favorable to Temple in this report were kept from his trial attorney.

In 2015, David Temple’s appellate attorneys secured a new hearing in the case. They made their case to the judge that evidence was withheld at the time of Temple’s trial. Kelly Siegler, who prosecuted the case against Temple, was called to testify.

Kelly Siegler testified at David Temple’s hearing and said she followed the law. She did allow that certain things were not shared with the defense at the time of trial, but says that was according to the law and rules of the prosecutor’s office at the time.

At the end of the months-long hearing in 2015, Judge Larry Gist sided with Temple’s defense, listing 36 items of evidence that prosecutors should have turned over to the defense, or turned over too late to be of use. Judge Gist recommended Temple be given a new trial, but his opinion was a recommendation. The Texas Court of Criminal Appeals would make the final call.

In November 2016, David Temple’s conviction was overturned by the highest criminal appellate court in Texas -- the Texas Court of Criminal Appeals. Temple is shown with his attorney, Stanley Schneider, following his release from prison.

Despite the court ruling. Belinda’s family says they still believe that David killed Belinda.

On Dec. 28, 2016, David Temple was released from prison. His brothers and parents were waiting to greet him. Temple told “48 Hours” that seeing them and being able to hug them like that was a “sweet, sweet joy.” Here David is hugging his father.

 “48 Hours” explores what’s next in the case in “The Alternate Suspects.”