Donald Trump Jr received and opened a letter containing an unidentified white powder inside of it Monday evening, sources tell ABC News.

The former president’s eldest son returns to testify in his father’s civil fraud trial.

After the New York AG rested her civil fraud case against Donald Trump last week, the defense will present its case beginning Monday with testimony from Donald Trump Jr.

ABC News’ Aaron Katersky has the details on Donald Trump, Jr. and Eric Trump’s testimony in court today.

The former president’s son told the judge Wednesday he had “no specific knowledge” about the financial documents at the heart of the case.

ABC News’ Olivia Rubin has the details as Donald Trump, Jr. takes the stand in the former president's civil fraud trial.

ABC News investigative reporter Olivia Rubin joins ABC News Live anchor Diane Macedo to break down the latest in Trump legal woes.

Donald Trump Jr. is expected to face questions about his role in managing his father's revocable trust, which was set up by Trump to hold the company's assets while president.

The Trump Organization's $250 million fraud trial becomes a family affair Wednesday when Donald Trump Jr. becomes the first of Donald Trump's children to take the stand.

New York's attorney general spoke to Ivanka and Donald Trump Jr. in its investigation into how the Trump Organization valued properties it owned.

The president's oldest son met with the committee on Tuesday.

The House select committee investigating the Jan. 6 Capitol attack is expected to meet with Donald Trump Jr. in the coming days, sources familiar with the matter tell ABC News.

The House Jan. 6 committee on Friday interviewed Kimberly Guilfoyle, the fiancee of Donald Trump Jr. and a GOP operative and fundraiser.

Trump Jr. is the second of the president's children to test positive.

And a judge in El Paso, Texas, is ordering the shutdown of nonessential businesses in the hard-hit area. ABC's Mona Kosar Abdi reports.

Twitter has temporarily limited the account belonging to Donald Trump Jr, President Donald Trump's eldest child, after he posted content that violated company policy.

President Donald Trump’s son, Donald Trump Jr., appeared on ABC’s The View on Thursday.

Trump Jr. apologized for how President Donald Trump treated the late Sen. John McCain. Both Trump Jr. and girlfriend Kimberly Guilfoyle bemoaned treatment from the left of the Trump family.

The Harris campaign fired back saying "this is the same type of racist attack his father used to attack Barack Obama. It didn't work then and it won't work now."

"This has been an 11-year battle," according to a defense attorney.

Donald Trump Jr. will be interviewed again by the Senate Intelligence Committee in mid-June in a closed-door hearing.

Donald Trump Jr. is expected to testify before the Senate Intelligence committee behind closed doors in June.

Donald Trump Jr has agreed to meet with the Republican-controlled Senate Intelligence committee for another interview, according to sources familiar with the matter.

McConnell predicts "happy ending" to Senate Intelligence Committee probe.

President Trump’s eldest son, Donald Trump Jr, has been subpoenaed to appear before the Senate Intelligence Committee, three sources familiar with the matter say.

The House Judiciary Committee voted to hold Attorney General William Barr in contempt of Congress for refusing to turn over the full Mueller report.

The president's eldest son made a surprise intervention in the Brexit debate.

Investigators are planning to ask Donald Trump Jr. to return to Capitol Hill.

Donald Trump Jr. posted on Instagram that his father's tweet about Warren was "savage."

The president's son spoke about how the senator helped rebuild their relationship after the election.

Trump Jr. and his wife, Vanessa, announced plans to divorce after 12 years of marriage and having five children together.

"We will always have tremendous respect for each other," they said.

A Massachusetts man was arrested for allegedly sending a letter with white powder addressed to Donald Trump Jr. in New York.

Trump Jr. 'liked' Twitter posts that contained conspiracies about the shooting.

Donald Trump Jr.'s wife was taken to a hospital in New York City today after opening a package at home that contained an unknown white powder, according to authorities.

The letter was sent to the Trumps' New York apartment.

The president's son said such accusations are terrible.

Committee "integrity and credibility should never be in question,” he wrote.

The president's son refused to answer questions about what he told his father about a 2016 meeting with a Russian lawyer.

The president's son was questioned largely by Democratic lawmakers.

The president's son was questioned about his 2016 Trump Tower meeting with a Russian lawyer.

The president's oldest son was in Kansas to attended a Kobach fundraiser.

The committee already met with four participants of a 2016 Trump Tower meeting.

He says he spoke with WikiLeaks during the 2016 campaign via Twitter

The messages began during the campaign, and his emails reveal that campaign officials knew about his contacts with WikiLeaks.

The president's son also attended a campaign fundraiser for the GOP congressman.

Investigators said questions remain.

The president's son spoke behind closed doors as committee staffers focused on his meeting with a Russian lawyer during the campaign.

Republicans were frustrated and surprised after President Trump sided with Democrats, but today, more of them changed their tune.

His meeting with a Russian lawyer will likely be discussed.