In 1770, if you asked who was the most famous "Adams" family member in the royal colony of Massachusetts (and in British North America, for that matter) the answer was Samuel Adams. Sam Adams was the leading "troublemaker" or rebel rabble rouser of the day. He was the first (and probably greatest) American radical revolutionary in our history. He organized the "Sons of Liberty" in Massachusetts in the late 1760s, and used them to bedevil the British government and it's Tory supporters (including Anne Hutchinson's descendant, Lt. Governor Thomas Hutchinson) on matters regarding taxation and political power.
The high point (or first high point - better ones were in store from Old Sam in the next five years) came in March 1770, when Sam caused a mob to pelt one or two unwanted British soldiers doing sentry duty on Boston Common during a snow storm. The soldiers sent for aid, and more soldiers arrived under a Lt. Pearson. Pearson tried to control the situation, but somehow it got out of hand: the soldiers got tired of being hit by snow, rocks, and other objects. Finally they fired into the mob, and killed five people, including Crispus Attucks, the first African-American martyr for liberty in our history.
Soon "the Boston Massacre" horrified the entire continent - aided by Sam Adams' friend, Paul Revere's picture of the event, complete with dead bodies and gore in the streets. Pearson and the soldiers were arrested. They needed an attorney.
Sam was amazed when he learned the soldiers hired cousin John. He knew John was a total patriot, and was amazed at his willingness to accept the brief. John told him (and others) that he had not dropped his views of quartering unwanted soldiers in Boston, or paying unwanted (and questionable) taxes to support the British government. But he was also willing to represent the soldiers so they could have a fair trial. Begrudgingly Sam and the others accepted John's decision. He was assisted by Josiah Quincy, a young, brilliant lawyer and patriot, who would die of tuberculosis in 1775, just before Lexington and Concord.
Sam Adams might have been less happy about John's choice if he had any idea of what would happen. John Adams is regarded today as one of the two greatest American lawyers who achieved the Presidency (the other is President Benjamin Harrison, a fantastically successful attorney in all kings of law cases). Adams managed to show to the jury that the soldiers were all under great duress from the mob, and the shooting was a reaction, not a planned murder. He won acquittal for Pearson and the soldiers.
It was the last time John Adams would help the British. It led to one peculiar follow-up. In 1784 Adams was America's first Minister to Great Britain. He was walking in London when he accidentally noticed a man who was staring back at him. It was Pearson, now living in London following the Revolutionary War. Both men realized who each other was. Did they have a drink together? No. Both were quite embarrassed at the meeting that reminded each of events from fourteen years before. They nodded, and went their separate ways. Apparently that was the last time they saw each other.