从那以后的日子里暗杀企图关于前总统唐纳德·特朗普(Donald Trump)，事情已经开始变得明朗起来嫌疑枪手在做什么在袭击的准备阶段。
克莱尔顿运动员俱乐部的律师向ABC新闻证实，在枪击事件的前一天，托马斯·马修·克鲁克斯去了当地的一家射击俱乐部，在步枪射击场练习。
根据执法部门的消息，这名20岁的男子在事件发生前不久购买了弹药，既有在线购买，也有亲自购买。
消息人士称，他要求他的雇主——一家他在其中担任饮食助手的疗养院——在枪击发生当天休假，但表示他第二天就会回来。
托马斯马修克鲁克斯未注明日期的照片。
消息人士称，在暗杀企图发生的当天，他问他是否可以借用他父亲的AR-15式步枪，说他打算去一个射击场。因为克鲁克斯的父亲之前曾让他用这把枪打靶，所以他并不怀疑他的儿子正在策划任何令人担忧的事情。
那天，克鲁克斯去了当地的一家枪支商店，在那里他买了50发5.56毫米的子弹。他还在一家家得宝(Home Depot)停下来买了一把5英尺长的梯子，尽管在现场没有发现梯子，也不认为梯子是用来上屋顶的。
然后，他开车去宾夕法尼亚州巴特勒的特朗普集会，把车停在大约三分之一英里外的一个加油站。
枪击发生前至少一个小时，有人看到克鲁克斯在集会区附近走动。视频中出现了克鲁克斯由匹兹堡ABC子公司WTAE获得下午5点06分，在特朗普集会的边界外踱步，大约在第一次开枪前一小时五分钟。
根据执法部门的消息，在枪击前几分钟，有人看到他在磁力计附近走来走去。执法部门消息人士称，一些目击者称他是一个可疑的人。
据消息人士称，他随后走向附近的一栋建筑，爬上空调机组，直到他能够登上相邻建筑的屋顶。从那里，他搬到了旁边一栋更高的建筑上。
就在克鲁克斯开火之前，集会者在屋顶上发现了他，并试图向特勤局报警。
在周三的一次非机密简报中，执法官员表示，特勤局狙击手第一次在屋顶上发现克鲁克斯时，与他向特朗普开火时相隔了20分钟。他们说，在枪击发生前62分钟，他被确认为嫌疑人。
巴特勒镇警官试图阻止枪手，爬上屋顶接近他，但克鲁克斯用枪指着警官，促使警官撤退，据巴特勒县警长迈克尔·t·斯卢普说。
就在这时，克鲁克斯开始向特朗普开枪，特朗普在那一刻转头看着大屏幕，这可能救了他的命。
据执法官员称，一名特勤局狙击手向克鲁克斯开枪还击，26秒后击中其头部致其死亡。
What Thomas Matthew Crooks did in hours leading up to attack on former President Trump
In the days sincethe assassination attempton former President Donald Trump, the pieces have begun to come together aboutwhat the suspected shooter was doingin the lead-up to the attack.
The day before the shooting, Thomas Matthew Crooks went to a local shooting club and practiced on the rifle range, counsel for the Clairton Sportsmen's Club confirmed to ABC News.
The 20-year-old purchased ammunition shortly before the incident, both online and in-person, according to law enforcement sources.
He asked his employer -- a nursing home where he worked as a dietary aide -- to take the day off on the day of the shooting, but said he would be back as soon as the next day, sources said.
Undated photo of Thomas Matthew Crooks.
On the day of the assassination attempt, he asked if he could borrow his father's AR-15-style rifle, saying he planned to go to a shooting range, sources said. Because Crooks' father had previously let him use the gun for target shooting, he was not suspicious that his son was planning anything of concern.
Crooks went to a local gun shop that day, where he bought 50 rounds of 5.56 mm ammo. He also stopped at a Home Depot to buy a 5-foot ladder, though it was not found at the scene and is not believed to have been used to access the roof.
He then drove to the Trump rally in Butler, Pennsylvania, parking about a third of a mile away at a gas station.
For at least an hour before the shooting, Crooks was seen walking around near the rally area. Crooks was seen in videoobtained by Pittsburgh ABC affiliate WTAEpacing just beyond the boundaries of the Trump rally at 5:06 p.m., around one hour and five minutes before shots were first fired.
He was also seen walking around near the magnetometers minutes before the shooting, according to law enforcement sources. Some witnesses reported him as a suspicious person, law enforcement sources said.
He then made his way to a nearby building, climbing up air conditioner units until he was able to get on the roof of an adjacent building, according to sources. From there, he moved onto a taller building next to it.
Just before Crooks opened fire, rallygoers spotted him on the roof and tried to alert the Secret Service.
In an unclassified briefing Wednesday, law enforcement officials said 20 minutes passed between when Secret Service snipers first spotted Crooks on the roof and when he opened fire on Trump. He was identified as a person of interest 62 minutes before the shooting, they said.
A Butler Township police officer attempted to stop the shooter, climbing up the roof to approach him, but Crooks pointed his gun at the officer, prompting the officer to retreat, according to Butler County Sheriff Michael T. Slupe.
It was at this point that Crooks began firing his weapon toward Trump, who at that moment turned to look at a Jumbotron, possibly saving his life.
A Secret Service sniper shot back at Crooks, fatally shooting him in the head 26 seconds later, according to law enforcement officials.
