The National Transportation Safety Board was not aware that Greg Biffle's wife, Cristina Grossu, had texted her mother moments before their plane crashed. "At this time, we are not aware of that," Michael Graham, 45th Member of the NTSB, said in a press conference on Friday, December 19, when answering a reporter's question about Grossu's text message. "If somebody is aware of a text or anything like that, please make us aware of it and let us know via email and then we'll contact you," Graham continued. "Same with the videos. If you have a video, contact us and we'll give you a way to send it to us." Grossu's mother, Cathy Grossu, shared the last text message from her daughter with People after news of her death broke on Thursday, December 18. "She texted me from the plane and she said, 'We're in trouble.' And that was it," Cathy recalled. "So, we're devastated. We're brokenhearted." NASCAR Driver Greg Biffle's Fatal Plane Crash: Everything We Know So Far NASCAR legend Biffle, along with his wife Cristina, their 5-year-old son Ryder and Biffle's teenage daughter from his past marriage, Emma, died in a plane crash on Thursday. Family friend and NASCAR driver Craig Wadsworth, pilot Dennis Dutton and his son, Jack, were also onboard the aircraft and died in the crash. News broke on Thursday that the aircraft was returning to the Statesville Regional Airport in North Carolina when it crashed and burst into flames. The plan was in the air for approximately 10 minutes before hitting the ground. Cathy told People on Thursday that the family was going on a "birthday trip" together. "To see the horrific way that it ended, it's just, it is so hard to bear. I cannot believe they're gone," she added. Family members of the deceased have since released a statement regarding the incident. "We are devastated by the loss of our loved ones," they began. "This tragedy has left all of our families heartbroken beyond words." Biffle and Cristina were remembered as "devoted parents and active philanthropists whose lives centered around" both Ryder and Emma. The statement remembered Emma as "a wonderful human being with a kind soul who was loved by many people" and Ryder as "an active, curious and infinitely joyful" kid. Greg Biffle Plane Crash: Identities of 3 Additional Fatalities Revealed "Each of them meant everything to us, and their absence leaves an immeasurable void in our lives," the statement concluded. "We ask for privacy, compassion and understanding as we grieve and begin to process this unimaginable loss. We are grateful for the kindness and support that has been extended to our families during this incredibly difficult time." The NTSB press conference on Friday was set to answer lingering questions about the tragedy. While the investigation has just started, members of the NTSB urged witnesses to come forward with any information they might have. There are not many details to report just yet, it seems. Member Graham told reporters on Friday that they are still unclear who was piloting the plane. "At this time, we have been unable to verify who was flying the airplane. We do know three of the occupants did possess a pilots license but we have been unable to verify this at this time," he said. "That is one of the things we're working on."