investigation agent
collaborator
An agent (an individual, organization, group or another legal entity) who provides support to an investigation. The support may include funding, design, implementation, data analysis or reporting. The responsible party is responsible for confirming all collaborators before listing them.
https://www.who.int/ictrp/network/trds/en/
Leon Li, Asiyah Li, Oliver He
investigation collaborator
https://prsinfo.clinicaltrials.gov/definitions.html#Collaborators