As it is presented on the Police site below, „Δ stands for „împuternicit”:
Împuternicit Șeful Poliției Municipiului X (Chief of X Municipality Police)

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Note added at 16 hrs (2020-03-28 13:12:58 GMT)
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Yes, I think it is, as these accreditations are given for 6 months, in order for somebody to be able to be a „chief” without passing the examination required by law.

The (Romanian) letter "î" stands (in this context) for (the Romanian word) "Împuternicit" which could be (temporarily) named/authorized for a certain position, ACTING AS....
http://legislatie.just.ro/Public/FormaPrintabila/00000G14FSR...
“Condiţiile împuternicirii
(1) ÎMPUTERNICIREA reprezintă exercitarea cu caracter TEMPORAR a unei funcţii de conducere, pe posturi vacante sau ai căror titulari nu sunt prezenţi în unitate mai mult de 30 de zile calendaristice consecutiv (exclusiv perioada concediului de odihnă) ori ai căror titulari sunt împuterniciţi să îndeplinească atribuţiile ALTOR FUNCȚII prevăzute cu salariu de comandă.
(2) Poliţistul care urmează să fie împuternicit trebuie să îndeplinească condiţiile de studii prevăzute în fişa postului şi să nu se afle sub efectul unei sancţiuni disciplinare.”

https://dexonline.ro/definitie/împuternicit
“împuternicit2, ~ă (Jur) (Persoană) care este autorizată să săvârșească ceva în numele altcuiva Si: mandatar, plenipotențiar, reprezentant.”
https://kywnewsradio.radio.com/articles/news/acting-police-c...
“After the sudden resignation of Richard Ross last week, acting Commissioner Christine Coulter has been fielding phone calls from District Attorney Larry Krasner, U.S. Attorney Bill McSwain, the FBI, and police union President John McNesby, to name a few.”
https://study.com/articles/acting_manager_vs_interim_manager...
“Comparing Acting Managers to Interim Managers”
“The difference in ACTING managers and INTERIM managers primarily exists in the designation of the position, rather than the roles. For all intents and purposes both job titles encompass the exact same job duties and responsibilities. Acting managers are employees who are asked to assume the role of manager temporarily, usually due to the actual manager being away on vacation or leave, while interim managers are temporary positions meant to fulfill a tentative role that isn't needed beyond the duration of that position. “
I'd go with Acting before Interim in this case...
Good luck!

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Note added at 1 day 21 hrs (2020-03-29 17:48:10 GMT)
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I believe this position to be temporarily assigned, hence the (Romanian) letter "î" in front of the position description...

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Note added at 13 days (2020-04-10 03:11:24 GMT)
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The whole phrase has to be translated as asked.