(CNN) -- It's perhaps the unanswered questions after Brandon Goode's death that will haunt his parents the most.
"Words do not exist to express the measure of our sorrow and sadness," Ricke and Connie Goode said in a statement issued Wednesday to CNN affiliates WESH and Central Florida News 13. "Whether mental illness, substance abuse or something else, we are a family searching."
Brandon Goode, 18, and Alexandria "Alex" Hollinghurst, 17, both of Davenport, Florida, are accused of fatally shooting a police officer before apparently committing suicide.
Windermere police Officer Robert German called for support after witnessing Goode and Hollinghurst -- who had been reported missing -- walking along a street early Saturday. But when backup arrived, German was found lying on the ground, suffering from a gunshot wound, according to Polk County authorities.
German, 31, was later pronounced dead at an Orlando hospital; the teens' lifeless bodies were discovered under brush not far from where German had been shot, county authorities said.
A five-year veteran with the Windermere Police Department, German had just returned to the force after being on "light-duty status" following surgery for an injury he suffered several months ago, Windermere Police Chief David Ogden said.
"All he wanted to do is be a cop," the chief said. "Officer German was a good cop. He was one of the finest police officers that we had in this agency."
The days leading up to the celebrated officer's death weave a complicated web that has left investigators puzzled over what happened.
Just two days before the shooting, the two teens ran away from home, leaving only letters behind for their families to find.
"To my loving parents, I am sorry for all the pain and misery I have brought you both, not just now but from these past few years as well," begins Brandon Goode's note, hand-written in neat, even letters.
"I don't want to go through life knowing because of my mistakes that I amounted to nothing and was there fore (sic) a disappointment. Don't take that as me putting the blame on you because that is the furthest thing from the truth. Both of you have been so amazing with your constant help and support through my life."
Goode was arrested earlier this year for possessing alcohol while underage and possession of marijuana and had been arrested in 2012 for an aggravated assault on his mother, according to incident reports from the Polk County Sheriff's Office.
"I love you with all my heart," the letter reads. "Please don't be sad, this is what I want now, I get to die peacefully with the woman I love, the woman of my dreams, my fiancé (yes we were engaged!). I miss you both so much already."
Hollinghurst penned loving missives addressed to her sister and father, but to her mother, she directed a bitter letter that suggests the two had a turbulent relationship.
"Thank you, for trying to talk and understand me after me being honest, after trying to fix things, thank you for turning a conversation about depression and suicide into something about you," the letter says. "If I had stayed another minute I would have painted the walls and stained the carpets with my blood, so you could clean it up."
Once the letters were found, the couple's parents called police to alert them to the teens' disappearances.
Using cell phone tracking technology, Kissimmee police officers found the two parked in Goode's car. When the officer asked Goode to step out of the automobile, he "cranked the vehicle, put the vehicle in drive and sped away," according to a Polk County Sheriff's Office incident report.
Later that day, Kissimmee police filed a warrant to charge Goode with resisting a law enforcement officer without violence and reckless driving.
The next day, German encountered the duo, stopped them and called for assistance, police say. The responding deputies found German "lying on the roadway, mortally wounded," the Orange County Sheriff's Office said. The deputies performed what is called a tactical rescue, using a patrol car to shield their fallen comrade.
That's when they heard two gunshots.
Upon searching nearby woods, Orange County sheriff's deputies found Brandon Goode and Alex Hollinghurst dead, lying in some brush, from what are believed to be self-inflicted wounds.
Windermere, just west of Orlando, is known for its luxurious homes and close-knit community. German's death profoundly affected its residents.
"Windermere's heart is broken. I had the opportunity to spend some time with his family this morning, and one thing that his mother shared with me was how he loved to be an officer and how he loved working for Windermere," Mayor Gary Bruhn said in a news conference this week. "There's a real hole in our hearts right now."
A law enforcement processional and memorial service to remember German will be held Thursday.
Goode's parents acknowledged the tragedy in their statement.
"We cannot comprehend the senseless loss of Officer German's life, the death of Alexandria Hollinghurst and for our family, the loss of our 18 year old son, Brandon," the note says. "Our deepest sympathy and our heartfelt prayers go out to the friends and family of Officer German. We are so, so sorry to them for what happened and they will be forever in our prayers. We know a community grieves and like everyone else in our community, we ourselves are struggling to understand this most horrific tragedy. We have no answers, only questions."