Stephen Craig Paddock (April 9, 1953 - October 1, 2017) was an American mass murderer who committed a mass shooting in Las Vegas, Nevada on October 1, 2017, that left over 58 people dead and over 515 others injured.     He resided in Mesquite, Nevada and was the partner of Marilou Danley.     
Las Vegas Mass Shooting
Stephen Paddock was identified as the shooter in the Mandalay Bay Resort Shooting where at least 58 people were killed and over 500 others were wounded.    Just after 10:00 p.m. local time, Paddock firing from the 32nd floor of the Mandalay Bay hotel down at the Route 91 Harvest Music festival, which was located in a fairgrounds area on Las Vegas Boulevard, hitting several concertgoers. Paddock committed suicide by shooting himself in his mouth as a SWAT team closed in on him.   
Photos and videos from the concert festival also showed multiple victims, including people on the ground, bleeding. The worst mass shooting in U.S. history was first reported at about 10:05 p.m. local time, with Paddock firing for at least 10 minutes. The scene remained active at 3:30 a.m. and people were being told to stay away.    
Authorities had located 23 firearms inside the hotel room, which he checked into on Thursday September 28, 2017, along with two platforms set up to shoot from. Paddock also had cameras to see police arriving. He had swung a heavy hammer to smash out two windows to shoot at the unsuspecting crowd of festival attendees.   
Paddock had a “do not disturb” sign on the door for three days, so no housekeepers entered the room. 
He is believed to have used long range rifles. 12 of the rifles found in his hotel room were outfitted with a bump stock, which allows a semiautomatic rifle to fire rounds faster, mimicking an automatic weapon.  
Several pounds of ammonium nitrate, which is used to make explosives, were also found in Paddock’s car.   On June 21, 2017, Paddok was prescribed 50 10-milligram diazepam tablets by physician Dr. Steven Winkler.  Paddock purchased the drug under the brand name valium, without insurance at a Walgreens store in Reno on the same day it was prescribed. 
The class of drugs can trigger aggressive behavior and psychotic experiences. 
He was raised by a single mother. His father, Benjamin Hoskins Paddock, is notorious for being on the FBI's Ten Most Wanted list for robbing three banks and escaping from prison. Benjamin was diagnosed as psychopathic after his arrest in the late 1960s. 
Education & Career
Stephen Paddock held various federal jobs in the 1970's and 80's. According to the U.S. Office of Personnel Management, he was a mailman for the U.S. Postal Service in the mid-to-late 70's; an agent with the Internal Revenue Service from 1978 to 1984; and worked for the Defense Contract Audit Agency in 1984 and 1985.
In 2014 he paid $369,022 in cash for the home he shared with his girlfriend Marilou Danley in Mesquite, Nevada. He erected a mesh privacy screen around the property, and was forced to take it down after his neighbors signed a petition.  
He was much less private at a home he owned in Melbourne, Florida, giving a neighbor a key and telling him he could borrow tools if he kept an eye on the house during the time when he was out of town.  
Paddock was not known to Las Vegas before his death.     Paddock lived in a three-year-old, $396,000 two-bedroom home in the small retirement and golf community of Mesquite, Nevada, 80 miles north east of Las Vegas near the Arizona state border.   
Paddock was an avid gambler. According to his brother, Eric Paddock, he gambled successfully for 20+ years and was has been quoted saying, "It's like a job to him." An acquaintance recalls that he won a lot of money applying algorithms to gambling.
On multiple occasions, Stephen Paddock gambled more than $10,000 per day and, in some cases, amounts more than $20,000 and $30,000 at Las Vegas casinos, according to an NBC News source who read the suspect's Multiple Currency Transaction Report (CTR) and a casino gaming executive. 
According to a U.S. statute, a CTR is a Treasury- and IRS-mandated report that casinos have to file when "each transaction in currency involving cash-in and cash-out of more than $10,000 in a gaming day. 
Relationship with Marilou Danley
It has been reported that he frequently berated Danley. The supervisor of a Starbucks inside the Virgin River Casino in Mesquite, Esperanza Mendoza, says that he would verbally abuse her there when she asked to use his casino card to make a purchase.
Before the mass shooting, he wired $100,000 to Marilou's bank account in the Philippines. His brother Eric noted, however, that this was not abnormal for him to send, as he was incredibly wealthy.
An Australian acquaintance of Paddock's, who chose to remain anonymous, described Paddock as "extremely intelligent, methodical, conservative – guarded – and strategic. A planning, thinking type of guy." He particularly recalls him studying gun laws to know his rights to own weapons.
His neighbors from Reno described him as "extremely standoffish."
Sources indicate that he left a note on a side table of his hotel room. Despite this, the police have repeatedly stated that they do not know the motive and have yet to make public any details. 
Paddock was prescribed Valium on June 21, 2017, which can lead to aggressive behavior as a side effect.  Antidepressants have been present in other shootings such as the Columbine High School massacre, Virginia Tech massacre, and the Thurston High School shooting. 
Marilou Danley who was named a person of interest was also located by authorities, she is believed to be his roommate.     She was contacted overseas and was later dismissed as a person of interest in the shooting.  
Hours after the shooting, the Islamic State of Iraq and Levant (ISIL) claimed responsibility, though this was later refuted by an FBI spokesperson as the claim lacked any credible evidence.   
Many paid tribute to the Victims of the Mandalay Bay Resort Shooting through donations, memorials and vigils.
Planned additional attacks
The weekend of September 23, 2017, Paddock had rented a high-rise condo in a building that overlooked the Life Is Beautiful music festival featuring Chance the Rapper, Muse, Lorde, and Blink-182.   
Paddock also booked a room at the Blackstone hotel in the first week of August, during the Lollapalooza festival in Grant Park. The hotel on S. Michigan Ave. is located right across from the park.   
A second room was booked for August 3, 2017, and both rooms had an August 6, 2017 checkout, when Lollapalooza ended. Investigators also believe he may have scouted locations in Boston, Massachusetts.   
A federal official stated that authorities are looking into the possibility Paddock also planned a car bombing. The official wasn't authorized to discuss the matter publicly and spoke to The Associated Press on condition of anonymity.