WHEN IS AN ARREST WITHOUT WARRANT LAWFUL?

> A peace officer or private person may arrest without warrant:

1.    When,  in  his  presence,  the  person  to  be  arrested  has committed, is actually committing, or is attempting to commit an offense;

2.    When  an  offense  has  just  been  committed  and  he  has probable  cause  to  believe  based  on  personal  knowledge  of facts  or  circumstances  that  the  person  to  be  arrested  has committed it; and

3.    When  the  person  to  be  arrested  is  a  prisoner  who  has escaped  from  a  penal  establishment  or  place  where  he  is serving  final  judgment  or  is  temporarily  confined  while  his case is pending, or has escaped while being transferred from one confinement to another.

4.    In hot pursuit

A  POLICE  OFFICER  WAS  CHASING  A  PERSON  WHO  HAD  JUST COMMITTED  AN  OFFENSE.    THE  PERSON  WENT  INSIDE  A  HOUSE, SO  THE  POLICE  OFFICER  FOLLOWED.    INSIDE  THE  HOUSE,  THE POLICE   OFFICER   SAW   DRUGS   LYING   AROUND. CAN  HE CONFISCATE THE DRUGS AND USE THEM AS EVIDENCE?

> Yes.    The  plain  view  doctrine  is  applicable  to  this  case  because there was a valid prior intrusion.  The police officer inadvertently discovered  the  evidence,  he  had  a  right  to  be  there,  and  the evidence was immediately apparent.

WHAT IF THE OFFICER MERELY PEEKS THROUGH THE WINDOW OF THE HOUSE AND SEES THE DRUGS, CAN HE CONFISCATE THEM AND USE THEM AS EVIDENCE?

> He can confiscate them, without prejudice though to his liability for violation of domicile.
> He cannot use them as evidence because the seizure cannot be justified  under  the  plain  view  doctrine,  there  being  no  previous valid intrusion.

WHAT IS THE EFFECT IF A WARRANTLESS ARREST IS ILLEGAL?

> It  doesn't  render  void  all  other  proceedings,  including  those leading to the conviction of the accused nor can the state deprived of its right to convict the guilty when all the facts of record point
to his culpability 

Sec. 5. Arrest without warrant; when lawful. – A peace officer or a private person may, without a warrant, arrest a person:

(a)   When,   in   his   presence,   the   person   to   be   arrested   has committed,  is  actually  committing,  or  is  attempting  to  commit  an offense;

(b) When an offense has just been committed and he has probable cause   to   believe   based   on   personal   knowledge   of   facts   or circumstances that the person to be arrested has committed it; and

(c) When the person to be arrested is a prisoner who has escaped from  a  penal  establishment  or  place  where  he  is  serving  final judgment  or  is  temporarily  confined  while  his  case  is  pending,  or has  escaped  while  being  transferred  from  one  confinement  to another.

In  cases  falling  under  paragraphs  (a)  and  (b)  above,  the  person arrested  without  a  warrant  shall  be  forthwith  delivered  to  the nearest  police  station  or  jail  and  shall  be  proceeded  against  in accordance with section 7 of Rule 112.