Police want to identify a woman seen walking towards a Tory MP's office before a small box of human faeces was left outside.
The container was found near Siobhan Baillie's constituency office in Stroud, Gloucestershire, on 2 November, police said.
Officers would now like to speak to the woman shown - dressed in pink trousers - in connection with alleged harassment.
The incident was reported shortly after 1.30pm.
Speaking to the BBC about the incident earlier this week, Baillie said she found it "difficult to understand" why she was targeted.
She said: "There are plenty of ways to make a point about politics or governments without resorting to putting excrement in a box.
"Because of the nastiness we face, decent people are thinking twice about standing for public office."
Baillie became the Tory MP for Stroud in 2019.
She was also targeted in 2020 after giving birth to her daughter when she received abusive emails, calls and social media posts criticising her for going on maternity leave.
Watch: Conservative MP Siobhan Baillie feels baby kicking as she rises to ask Commons question
Gloucestershire Constabulary added in a statement: "Police have released CCTV footage of a woman they would like to speak to in connection with the harassment of an MP.
"An offensive item was left outside of the constituency office of Stroud MP Siobhan Baillie.
"The incident involving a small box containing human excrement was reported shortly after 1.30pm on Wednesday 2 November.
"Investigating officers have now identified a woman on CCTV who they would like to talk to further in relation to the incident.
"In the footage, the woman is seen wearing pink trousers and walking towards the MP's office.
"Anyone who can identify the woman or who has information which could help the investigation is asked to contact Gloucestershire Constabulary through the website, quoting incident 212 of 2 November."