19-year-old Miles Hannagan and his 18-year-old sister Charlotte were members of the Washington Memorial Drum and Bagpipe Band.
In fact, band president Colin Holland Drummond says they were following in the footsteps of their father, Paul, who is also a member of the band.
Drummond tells us, "Nowadays when, you know, teenagers are doing their thing and whatever, you didn't find that with the Hannagans. They were always together."
And they were all together Saturday night driving home from a performance at the Valley Forge Casino when their minivan was rear ended by a pickup truck that witnesses say was swerving erratically and traveling at a high rate of speed.
Investigator say the man behind the wheel was 25-year-old Thomas Muir of Media.
Uwchlan Township Police Chief Joseph Pontarelli explains, "During the initial investigation, it was determined that Mr. Muir was under the influence of alcohol - appeared to be - and at that time he was placed under arrest."
Investigators are also looking into Muir's cell phone records to see if he may have been texting at the time as well.
Miles and Charlotte, who were wearing their seat belts, were ejected from the vehicle and pronounced dead at the scene.
Their father, aunt, and uncle were treated and released from Paoli Hospital. Their mother, Maggie, remains in intensive care.
Meanwhile, a big tribute to Miles and Charlotte is already planned for an upcoming drum and bagpipe performance in the Lehigh Valley.
Drummond says, "The Allentown Saint Patrick's Day Parade, we're going to do a special, commemorative salute with the mass bands for Miles and Charlotte. So you know, there's support from everywhere. I mean, everyone is shattered."
Muir, who was not injured, remains held on $75,000 cash bail. His preliminary hearing is scheduled for next Tuesday.