ALBANY — Dean G. Skelos, the leader of the New York State Senate, and his son were arrested on Monday by federal authorities on extortion, fraud and bribe solicitation charges, expanding the corruption investigation that has cast a renewed spotlight on Albany’s intractable corruption problem.

The charges against Senator Skelos, 67, and his son, Adam B. Skelos, 32, were detailed in a six-count criminal complaint that quickly became mandatory reading material in the Capitol building. Politicians and their staff members pored over the 43-page complaint — an often titillating document that included references to burner phones, secretly taped conversations and strong-arm tactics that were on display even during the wake of a slain police officer.

Senator Skelos, a Republican from Long Island, was accused of taking official actions to benefit a small Arizona environmental company, AbTech Industries, and a large New York developer, Glenwood Management, that had financial ties to AbTech. Senator Skelos agreed to do so, according to the complaint, as long as the companies paid his son.

The arrests came just months after federal bribery and kickback charges led Assemblyman Sheldon Silver, a Democrat, to step down from his position as speaker.