Does Canadian Security and Intelligence Service (CSIS) have power of arrest?
The "security" component of the name connotes that they are sworn
peace officers with the power of arrest but I have never read of
anyone being arrested by them.

In the USA the FBI mandate includes counter-intelligence and
counter-terrorism duties. Do they have the power of arrest?
I saw lots of Effrem Zimbalist Jr as a kid so I think it is yes but
please indulge me anyway.

In the UK the MI-5 has counter-intelligence and counter-terrorism. 
Do they have the power of arrest?

Hello.

No, the Canadian Security and Intelligence Service (CSIS) does NOT
have power to arrest.

Here's an excerpt from a statement made by Ward Elcock, Director of
the Canadian Security Intelligence Service, June 24, 1998:

"...We are an information resource for government. We are not a police
force. We do not enforce the law. We do not arrest. We do not
prosecute. We support those who do."

source:  Canadian Security and Intelligence Service (CSIS)
http://www.csis-scrs.gc.ca/eng/miscdocs/kelly_e.html


Additional sources:

"CSIS agents do not have the power to arrest anyone whatsoever."
source: Collective Opposed to Police Brutality
http://www.tao.ca/~cobp/police-secrete-eng-txt.html

"How did CSIS, which does not have the power to arrest anyone,
convince Jabarah to sign..."
source: Kuro5hin.org: A Case of Injustice
http://www.kuro5hin.org/story/2002/8/2/2218/72703

----------------

The UK's MI5 also lacks the power to arrest.

sources:

"M.I. 5 ...
 They operate in the background and do not have the power to arrest
people. For this they have the Special Branch."
source: London Taxi Tour:
http://www.londontaxitour.com/london-taxi-tour-sights-river-mi5.htm

"Question 5
Does MI5 have the power to arrest people?
...(Correct Answer). A. No.
http://newsvote.bbc.co.uk/1/hi/programmes/true_spies/2327219.stm?markResults=true

"(MI5 has no power to arrest, for example - instead, it informs
Scotland Yard's Special Branch and they do the arresting."
source: Katya's Fun Facts: British and Russian Espionage
http://theory.lcs.mit.edu/~jherzog/Masks/FFBritsRussSpies.htm

----------

search strategy:
csis "power to arrest"
csis, "does not arrest"/"do no arrest"
mi5 "power to arrest"

I hope this helps.

---

Clarification of Answer by juggler-ga on 22 Jan 2004 20:05 PST

Hello.

I just noticed that you also asked about the FBI.  They have very
limited arrest powers.

"By themselves, FBI agents have limited power to arrest and no power
to punish those suspected of violating federal law. An FBI agent
investigates and reports, and when other government agencies make the
arrest, they often invite the FBI agent or agents who were involved
with the case, but merely as a courtesy."
http://www.princetonreview.com/cte/profiles/dayInLife.asp?careerID=64

"In an effort to bolster the FBI?s antiterrorism powers late last
year, Attorney General John Ashcroft signed a special order giving FBI
agents the power to arrest suspects under federal immigration
statutes. But Homeland Security lawyers now argue that Ashcroft?s
order became invalid when the INS, formerly part of Justice, moved to
Homeland."
http://www.msnbc.msn.com/Default.aspx?id=3068377&p1=0

Thanks Juggler.  And very quick too. 
I found the Katya reference to Cummings prosthetic leg amusing. Quite.

Thank you for the tip.
-juggler