diff --git a/deploy/packages/deb/debian/postrm b/deploy/packages/deb/debian/postrm
index 5df55135a..9ee1dca87 100755
--- a/deploy/packages/deb/debian/postrm
+++ b/deploy/packages/deb/debian/postrm
@@ -21,6 +21,8 @@ set -e
 
 case "$1" in
     purge)
+        # force kill all processes owned by emqx, if any
+        pkill -9 -u emqx || true
         rm -f /etc/default/emqx
 
         if [ -d /var/lib/emqx ]; then
@@ -38,9 +40,8 @@ case "$1" in
         if [ -e /etc/init.d/emqx ]; then
                 rm  /etc/init.d/emqx
         fi
-        # Remove User & Group, killing any process owned by them
+        # Remove User & Group
         if getent passwd emqx >/dev/null; then
-                pkill -u emqx || true
                 deluser --quiet --system emqx
         fi
         if getent group emqx >/dev/null; then
diff --git a/scripts/pkg-tests.sh b/scripts/pkg-tests.sh
index a88020dd5..dfb5d098f 100755
--- a/scripts/pkg-tests.sh
+++ b/scripts/pkg-tests.sh
@@ -131,6 +131,21 @@ emqx_test(){
                 exit 1
             fi
 
+            echo "try to install again and purge while the service is running"
+            dpkg -i "${PACKAGE_PATH}/${packagename}"
+            if [ "$(dpkg -l | grep ${EMQX_NAME} | awk '{print $1}')" != "ii" ]
+            then
+                echo "package install error"
+                exit 1
+            fi
+            if ! /usr/bin/emqx start
+            then
+                echo "ERROR: failed_to_start_emqx"
+                cat /var/log/emqx/erlang.log.1 || true
+                cat /var/log/emqx/emqx.log.1 || true
+                exit 1
+            fi
+            /usr/bin/emqx ping
             dpkg -P "${EMQX_NAME}"
             if dpkg -l |grep -q emqx
             then