He was also carrying an Apple laptop, a U.S. passport, a book authored by Trump and a letter to the president, Daily Mail reports.
The US Secret Service said the breach happened shortly before midnight on Friday.
Trump told reporters on Saturday that the United States Secret Service did a "fantastic job" stopping the intruder who scaled a White House fence late on Friday and entered the grounds.
It is not unheard of for intruders to scale the White House perimeter fence, and those that do are usually caught quickly and handed over to local police.
He was living in his auto, the sibling added, before calling Tran a "very good brother".
"This is really troubling", said Jonathan Wackrow, an ex-Secret Service agent.
That is when the officer stopped him, after which Tran said: 'I am a friend of the President. The intruder who was carrying a backpack was arrested by Secret Service officers, who also searched the backpack as a precautionary measure.
The backpack carried by the intruder was screened and searched, and no hazardous material was found, according the statement.
The White House security level was temporarily raised to "orange" - one of the highest - as a result of the intrusion.
Homeland Security Secretary John Kelly was briefed on the incident, according to the Washington Post.
When asked how he managed to get here, Tran replied: 'I jumped the fence, ' authorities said.
In 2014 a man made it past eight Secret Service agents with a three-and-a-half-inch folding knife in his trouser pocket.