Is there any case law where a person who sees a police officer on the way to the scene of an incident has a reasonable suspicion for detention?

Third, appellant's and his companions' evasive conduct immediately following their sighting of the officers is fertile evidence to support a reasonable suspicion for a detention. (People v. Souza, supra, 9 Cal.4th at p. 233; see Florida v. Rodriguez (1984) 469 U.S. 1, 6.) Even though there may be an innocent motive for a person's evasive conduct upon seeing police officers, it is still a relevant consideration for establishing reasonable cause to detain him or her. (People v. Souza, supra, 9 Cal.4th at p. 233.)