They spoke to more than 12 witnesses, subpoenaed 25, and were still pursuing it when your guy resigned.
From their press release:
Representative Gaetz has categorically denied all of the allegations before the Committee. Notwithstanding the difficulty in obtaining relevant information from Representative Gaetz and others, the Committee has spoken with more than a dozen witnesses, issued 25 subpoenas, and reviewed thousands of pages of documents in this matter. Based on its review to date, the Committee has determined that certain of the allegations merit continued review. During the course of its investigation, the Committee has also identified additional allegations that merit review.
Link: https://ethics.house.gov/press-releases/statement-regarding-matter-representative-matt-gaetz