investigate trump, but not elected officials? 

It's alright that the media investigates Donald J. Trump's transitioning/dissolving/blind trusting etc. his private businesses before taking office as POTUS. 
But to be equal, they should investigate elected officials who did not withdraw their votes from any measure or bill proposed or pending they had a personal or private interest in.
Just in Colorado alone, there are elected officials, former and present, who use their positions and taxpayers $'s to unjustly benefit (self-enrich). 
But they've yet to be investigated. 
Why?
Here's Colorado's Voting Recusal Provisions...What's your state's? 

VOTING RECUSAL PROVISIONS FOR COLORADO 

Colorado Constitution Art 5, Sec. 43: A member of the General Assembly who has a "personal or private interest" in pending legislation must disclose the fact of such interest and may not vote on the legislation.

Senate Rule 17, 41: Senators shall not vote on bills in which they have personal or private interests. If this is the case, they must disclose those interests before being excused. A senators is considered to have personal or private interests in measures if he:

• Has substantial economic interests in the measure distinct from those held generally by members of the same occupation or business, of if a close relative has such an interest,
• Has an interest in an enterprise that would be affected by the proposed legislation differently from like enterprises,
• Has a close relative or a close economic association with someone who has a financial interest in an enterprise that would be affected differently from others,
• Has a close economic association with, or has a relative who is, a lobbyist or lobbyist employer who is influencing legislation on which the legislator would be expected to vote,
• Accepts a gift, loan, service or other economic opportunity from someone who would be affected by or has interest in an enterprise that would be affected by the legislation. This provision applies when close relatives of a senator accept the same.

Senators are always allowed to vote for something that would adversely affect their personal or private interests.
House Rule 21: A request by a member to be excused from voting shall be made before the call for the ayes and noes has begun; any member desiring to be excused from voting on a question shall make a brief statement of the reasons therefor, and the question shall be put without further debate. A member who has an immediate personal or financial interest in any bill or measure proposed or pending before the General Assembly shall disclose the fact to the House, and shall not vote upon such bill or measure.
Colorado Revised Statutes 24-18-107. Ethical principles for members of the general assembly. ... In deciding whether or not he has a personal or private interest, a member shall consider, among other things, the following:

• (a) Whether the interest impedes his independence of judgment;
• (b) The effect of his participation on public confidence in the integrity of the general assembly; and
• (c) Whether his participation is likely to have any significant effect on the disposition of the matter.
  
  An interest situation does not arise from legislation affecting the entire membership of a class. If a member of the general assembly elects to disclose the interest, he shall do so as provided in the rules of the house of representatives or the senate, but in no case shall failure to disclose constitute a breach of the public trust of legislative office.