Definition: Given a document, generate a short title of the document. The title should convey the main idea/event/topic about which the document is being written. Note that URLs in the text have been replaced with [Link].
Input: Authorities discovered that Las Vegas  Nevada  shooter  Stephen Paddockâs  laptop had a missing hard drive during a search of  his  hotel room at the Mandalay Bay resort  according to a report.
ABC News reports that investigators have not been able to recover the missing device and suspect that  Paddock  removed the hard drive before shooting  himself  to death.
Authorities suspect that  Paddock  bought software that enabled  him  to erase files from  his  hard drive but could not confirm  he  used the software without examining the hard drive  a source told ABC News.
They are trying to piece together different aspects of  his  life  examining ties to friends  family  and associates. Authorities have also tried to discern a motive from  his  travel habits  health  and finances but to no avail.
Unlike other mass shooters   Paddock  has not left many traces of evidence.
But  he  is not the first mass shooter to destroy or conceal  his  digital footprint.
In 2007  Cho Seung Hui took the hard drive out of  his  computer and discarded  his  cellphone before opening fire on 32 people at Virginia Tech.
Steven Kazmierczak  who took the lives of five students at an Illinois college before turning the gun on  himself  in 2008  removed  his  laptopâs hard drive and tossed out the SIM card from  his  phone.

Report: Las Vegas Shooter's Laptop Missing Its Hard Drive