Definition: Given a document, generate a short title of the document. The title should convey the main idea/event/topic about which the document is being written. Note that URLs in the text have been replaced with [Link].
Input: The House Oversight Committee has opened an investigation into  Rob Porter 's White House employment while  he  was being accused of abusing  his  ex-wives.
 The probe  comes as the White House  more than a week into the scandal  has continued to offer shifting explanations of the circumstances of  Porter 's tenure as a top aide to President Donald Trump.
Wednesday morning  the Oversight Committee's chairman  Rep. Trey Gowdy  R-S.C.  sent White House chief of staff John Kelly and FBI Director Christopher Wray letters asking for details about  Porter 's background check and the decision to keep him on the job before he quit last week.
Gowdy  in his letters  specifically asked for "the date on which any White House employee became aware of potential derogatory or disqualifying information on  Porter  from the date of  his  appointment to February 12  2018  and which individual was notified."

Read Trey Gowdy's letters to Wray Kelly over Porter abuse probe